3.2 BOT

STUDY GUIDE

BOTANY OF TURF PLANTS

B Hannan

+64 6 356 8090 [email protected] www.nzsti.org.nz

© 2020, NZ Sports Turf Institute Ltd. This document has been produced by the New Zealand Sports Turf Institute [NZSTI], for its students. All content, excluding that which is referenced as being the work of another individual or organisation, remains the property of NZSTI. No part of this publication may be reproduced in any form, without the express written permission of NZSTI. Contributors Authors: Brendan Hannan Learning Designer: Angela Stratford Graphic Designer: Lainey Te Whatu & Lindsay Robertson Referencing this publication Hannan, B. (2020). Botany of Turf Plants: Study guide. Palmerston North: NZ Sports Turf Institute Ltd.

Course content The Botany of Turf Plants course includes an introduction to plant taxonomies (the scientific classification system), the botanical names of common turf plants, the identifying features of turf plants, desirable turf species and undesirable turf species (grasses and weeds), and how the growth and development of turf plants can best create the ideal turf surface for each sport.

Learning outcomes By the end of this course, students will be able to: ~ Demonstrate understanding of turf plant and grass reproduction and identification, turf growth and development, and the advantages and disadvantages of cultivars of turf species for sports turf use. ~ Identify common turf plants. ~ Identify common weeds of turf and describe the detrimental effects of weeds on turf. ~ Describe the ways in which common turf weeds survive and spread. ~ Describe the features and spread of moss and algae on turf surfaces.

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BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

Contents Course content

iv

Learning outcomes

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1. Classifying plants

2

Biological taxonomy

4

Botanical classification

8

Reading and writing the scientific names of plants

14

Cool and warm season grasses

15

2. Parts of a turfgrass plant

18

Turfgrass leaves

19

Turfgrass stems

23

Turfgrass flowers

25

Turfgrass roots

27

3. Common desirable sports turf plants

29

Cool season turfgrasses

30

Warm season turfgrasses

38

Broadleaf turf plants

43

4. Managing sports turf plants

46

The demands of sport

46

Turf plant growth and development

48

5. Sports turf weeds

61

Grass weeds

63

Broadleaf weeds

63

Mosses, algae and liverworts

65

Detrimental effects of weeds

68

Weed survival and spread

70

Glossary

75

References

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1. Classifying plants A turf plant is defined as any plant we need to manage in a sports turf sward (pronounced to rhyme with ‘sword’ but with the ‘w’ sound, an area of turf ). We describe the turf plant or plants that we want to grow in a particular sports turf area as desirable plants. Often this is just a single species across a large area. The basic definition of a weed is “a plant growing in the wrong place”. Hence, Poa annua, Kikuyu, etc, may in fact be a desirable plant species in some situations, but a weed in others. Any plant in the wrong place can also be called an undesirable plant. Also defined as turf plants are desirable broadleaf turf plants used in bowling greens - such as cotula and starweed - and undesirable broadleaf weeds such as the English daisy, hydrocotyle and plantain. In a group of their own are the mosses, liverworts and algae, which are also considered turf plants that need to be managed within the context of sports turf management. Table 1 provides a list of turf plants that are common in New Zealand. This list is in no way complete but is an indication of the types of turf plants you will come across in sports turf management. Table 1: Examples of turf plants commonly found in New Zealand. Grass Plants

Broadleaf Plants

Other

Desirable

Undesirable

Desirable

Undesirable

Undesirable

Browntop

Carpet grass

Cotula

Buttercup

Moss

Buffalo grass

Summer grass

Starweed

Cape weed

Liverworts

Carpet grass

Crowsfoot

Catsear

Algae

Chewings fescue

Kikuyu

Chickweed

Couch

Poa annua

Clover

Creeping bent

Sweet vernal

Cudweed

Hard fescue

Yorkshire fog

Dandelion

Kentucky bluegrass

Dock

Perennial ryegrass

Hawksbeard

Poa annua

Hydrocotyle

Red fescue

Onehunga weed

Tall fescue

Oxalis

Kikuyu

Pennyroyal Plantain

What these plants have in common that makes them ‘turf plants’ is that they can survive frequent mowing. In fact, turf plants have a number of basic features in common, notably: ~ They can survive and grow well under close (low and frequent) mowing (both desirable and undesirable turf plants). ~ They can generally put up with wear (being often walked on or driven over)and can recover quickly (both desirable and undesirable turf plants). ~ They have features that allow them to reproduce and spread in often difficult and unnatural conditions (both desirable and undesirable turf plants). ~ They have qualities such as colour and texture desirable to the sports they are used for (desirable turf plants). ~ They can grow densely over a surface (desirable turf plants). 2

BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

Figure 1: Both desirable and undesirable turf plants can grow, spread and reproduce well in a sports turf environment. Crowsfoot, plantain, and Onehunga weed grow among a ryegrass lawn (left), while a native daisy has established itself in a browntop croquet lawn (right). Photos: NZSTI Turf managers need to be able to identify the desirable species they have in their sports turf area, and then ensure that management practices are helping this species to grow well.

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Biological taxonomy For centuries, people have wanted to discover different living organisms on this planet and share information about them. With over five million different kinds of organisms, classification systems are required to distinguish (identify differences) between them. Without an international system, information sharing and studying individual organisms would be far too complex and unreliable. The naming and grouping of all living things (including turf plants) is called taxonomy. This was most successfully developed in the 1700s by Swedish botanist, physician and zoologist Carolus Linnaeus. This classification system is the basis of what we use today. The classification system organises living things into groups of things with similar characteristics that share a common ancestor. Linking an individual type of organism to its wider group can help us to better understand its characteristics, such as the habitat it likes to live in, or how it reproduces. The biological taxonomy system starts with domains and then very general groups known as kingdoms, which cover all living creatures. The next level is called phylums, which are also referred to as divisions. These groups are subdivided several more times before finally classifying each unique type of organism.

Figure 2: The different levels used in biological classification. Diagram: AdobeStock 4

BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

Plant names As knowledge grew through taxonomy, it became necessary to know the names that others had given to each organism in order to learn what was known about them and report new information. To begin with, familiar plants were given common names but this became misleading, particularly when exchanging information with people from different parts of the world. For example, couch (pronounced “kooch”) grass in the turf industry in New Zealand is also known as Bermuda grass and Indian doab in NZ agriculture, and in other parts of the world. When different languages are involved, the problems became hopelessly complex. For this reason, biologists refer to organisms by Latin names, and the Latin plant names are recognised by international organisations of botanists. Botanical nomenclature ((pronounced “no-MEN-cluh-chur”) is the formal, scientific naming of plants based on the plant’s place in the taxonomic system. Because of this, the plant’s classification and name show the other plants that shares similar characteristics with. On the next two pages is part of the biological taxonomic system that covers turf plants. You can see that it starts with the Plantae Kingdom on the left, and then divides plants into different groups as we go down level by level. You can refer back to this diagram as you read through the text after it which describes the levels and their significance for turf plants.

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Plantae

Seed production

Reproduce without seed

Phylum/Division Kingdom Kingdom

Class Class

Angiosperms (fruits bearing seeds internally

Monocots

Dicots

Poaceae

Asteraceae (Daisy family)

Plantaginaceae (Plantain family)

Order Family Order Family

Gymnosperms (external seed bearing structures mainly conifers)

Subdivision Subdivision

Chloridoideae (Eragrostoideae) Warm season grasses C4

Panicoideae Warm season grasses C4

Subfamily Subfamily

secundatum secundatum

Stenotaphrum Stenotaphrum

Longistylum var. clandestinum Longistylum var. clandestinum

compressus compressus

affinis affinis

Zoysia

Agrostis

Aveneae

Cynodon

Egmont Sefton

Colonial bentgrass Browntop

Creeping bentgrass

Penncross Penn A-4 Stolonifera var. palustris capillaris

Korean velvet grass Mascarene grass (Ornamental use only) Marathon III

Manilagrass

Japanese or Korean grass

Hybrid Cynodon Hybrid couch (Aust.)

South African couch

Couch Common Cynodon Common couch (Aust.)

Durban grass Sweet smother grass Durban grass Sweet smother grass

Kikuyu grass Kikuyu grass

Broadleaf carpetgrass Cowgrass (Malaysia) Broadleaf carpetgrass Cowgrass (Malaysia)

Narrow leaved carpetgrass Narrow leaved carpetgrass

Bahiagrass (bunch type growth habit) Bahiagrass (bunch type growth habit)

Seashore paspalum Seashore paspalum

Buffalo grass (Aust. & NZ) St Augustinegrass (US) & NZ) Buffalo grass (Aust. St Augustinegrass (US)

tenuifolia

L.

Steud.

Hurcombe

(L.) Pers

Hocst. Ex Chiov

(Sw). P.B.

Chase

Fluegge

Swartz

(Walt) Kuntze

Centipedegrass China grass Centipedegrass Chinese Chinalawngrass grass Chinese lawngrass Queensland blue couch (Aust.) Serangoon (Malaysia) Queensland blue couch (Aust.) Serangoon (Malaysia)

Flawn Diamond Cavalier Royal

Meyer El Toro Crowne Palisades Emerald (Z japonica XZ. Tenufolia)

Tifgreen (Tifton 328) Tifdwarf Tifeagle Santa anna MS Supreme Tifway (419)

Skaapplaas

Wintergreen Windsor Green Greenlees Park Legend (C1) Plateau

Oklawn Centennial Oklawn Centennial Aussieblue Tropika Aussieblue Tropika Sir Walter Shademaster Palmetto ST85 ST95 Adalayd Salam Saltene Futurf Sea Isle 1 Sea Isle 2000 Common Argentine Pensacola

Cotula maniototo

matrella

japonica

Magennisii (c. dactylon X C. transvaalensis

transvaalensis

dactylon

Dactyloctenium australe Dactyloctenium australe

Pennisetum Pennisetum

Axonopus Axonopus

notatum notatum

vaginatum vaginatum

didactyla didactyla

Digiteria Digiteria

Paspalum Paspalum

Ophi urodes Ophi urodes

dispersa

squilida

maniototo

Cotula dioca

Common name Common name

dioica

(Munro) Hack (Munro) Hack

Authority Authority

Starweed Grasslands pahia

Cultivar Cultivar

triandra

Species Species

Eremochloa Eremochloa

Leptinella

Plantago

Genus Genus

Zoysieae

Chlorideae

Eragrosteae Eragrosteae

Paniceae Paniceae

Andropogoneae Andropogoneae

Tribe Tribe

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Pooideae (Festucoideae) Cool season grasses C3

Festuceae

Aveneae

Poa

Lolium

Festuca

Agrostis

Shadow II

nigrescens (syn. Rubra var. commutata)

Rough bluegrass

trivialis

L.

Supina bluegrass Colt Laser II

Kentucky bluegrass

supina

L.

Supra Supranova

Poa (NZ & Aust.) Annual bluegrass (US) L.

Midnight Bluestar

Perennial ryegrass

Italian ryegrass Annual ryegrass

Chewings fescue

Slender creeping red fescue

Strong creeping red fescue

L.

Lam.

L.

pratensis

annua

perenne

Arena

Seabreeze

rubra var. litroralis

multiflorum

Shademaster II

Blue fescue Sheeps fescue

ovina var. glauca rubra var. rubra

Hard fescue

SR 3200 Bighorn

Tall fescue

ovina var. duriuscula

Schrub

SR 3000 Discovery hard

arundinaceae

Red top

L.

alba Torpedo Coronado

Velvet bentgrass

L.

Colonial bentgrass Browntop

canina

capillaris

Creeping bentgrass

L.

Penncross Penn A-4

Stolonifera var. palustris Egmont Sefton

Korean velvet grass Mascarene grass (Ornamental use only)

Marathon III

tenuifolia

Manilagrass

Flawn Diamond Cavalier Royal

matrella

Botanical classification As we said earlier, this taxonomy applies to all living things: all types of animals and plants. We’ll now look at how it applies to the plants you are likely to come across in the sports turf industry. The classification of plants enables us to have a much greater understanding of turf management requirements for the turf plants we are managing. It allows us to understand the needs of the plant, the way it grows, the inputs required, and at what time of the year it grows. This gives us the knowledge to select species most suitable for our sports turf setting, and manage pests, diseases and weeds through an integrated (connected) process. As we go down from kingdom through to species, we can see how the plants share more and more characteristics.

Kingdom At the highest level, plants are classified under the Plantae Kingdom. Plants that are grouped together in the Plantae Kingdom are terrestrial (live on the land), do not move, eat or breathe, and are capable of making their own food through photosynthesis.

Phylum / Division The Division level (also known as Phylum) of the taxonomy sees plants classified as either seed-bearing or nonseed-bearing.

Non-seed-bearing plants These are a very basic and simple group of plants that do not flower or produce seed, but reproduce by spores. Examples of these plants in sports turf management are algae, mosses and liverworts.

Figure 3: Algal slime (left), moss (centre) and liverwort (right) are in the division of non seed-bearing plants which reproduce by spores. Photos: NZSTI

Seed-bearing plants Seed-bearing plants are further divided into gymnosperms or angiosperms.

Gymnosperms The gymnosperms are a group of seed-producing plants which includes conifers. The translation of gymnosperms is “naked seeds”. This references the fact that the seeds are produced on scales or leaves, which are often modified to produce cones or produced solitarily, such as yew and ginkgo trees. This distinguishes them from the Angiosperms, where the seeds are produced within a fruit. Gymnosperms are often seen in amenity areas of sports turf facilities and make up a number of our significant New Zealand native species. Some examples are kauri, totara, miro and matai.

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BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

Figure 4: Cone of a typical gymnosperm found in New Zealand, the kauri (Agathis australis). Photo: AdobeStock Angiosperms The angiosperms are a group of flowering plants with edible fruits containing seeds. The term “edible fruit” also includes seeds such as grass seeds. Animals feed on the fruits and berries, assisting with seed dispersal. Most turf plants, both desirable and undesirable will fall within this group, including warm and cool-season grasses, broadleaf weeds, and desirable broadleaf plants such as cotula and starweed.

Figure 5: Examples of angiosperms include (top row, from left to right): ryegrass, tall fescue, browntop, summer grass and sweet vernal, as well as (bottom row, left to right) starweed and Onehunga weed. Photos: NZSTI

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Class At the class level of the taxonomy, plants are divided into groups depending on how many leaves first emerge out of the seed: ~ monocotyledon, pronounced moh-no-coh-tuh-LEE-din, have one seed leaf, (“mono” meaning one), while ~ dicotyledon, pronounced die-coh-tuh-LEE-din, have two seed-leaves (“di” meaning two). These two groups are often referred to as “monocots” and “dicots”.

Figure 6: Monocots are named because they have one leaf growing from the seed, while dicots produce two leaves from the seed. Graphic: AdobeStock Further differences between monocotyledons and dicotyledons are identified in four distinct structural features: leaves, stems, roots and flowers. Note that this is a generalisation, and not all features are listed. For instance, dicotyledons can have both taproots and fibrous roots.

Figure 7: Key differences between monocotyledons and dicotyledons. Graphic: Carolina Biological Supply Company 10

BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

All of our grasses (both desirable and undesirable) are monocotyledons, while dicotyledons include the majority of sports turf broadleaf plants and weeds.

Figure 8: Examples of monocotyledons commonly found in sports turf in New Zealand. From left to right: browntop (Agrostis capillaris), couch (Cynodon dactylon), and toad rush (Juncus bufonius). Photos: NZSTI

Figure 9: Examples of dicotyledons commonly found in sports turf in New Zealand. From left to right: plantain (Plantago major), hydrocotyle (Hydrocotyle heteromeria), and cotula dioica (Leptinella dioica). Photos: NZSTI

Order The Order level of the taxonomy is not commonly used in plant classification, but can be used to group similar families. Most plant order names end in ”ales”. The plant order for most turfgrasses is Poales. The plant order for a broadleaf weed such as hydrocotyle is Apiales.

Family The family level of the taxonomy groups plants with similar flower, fruit and seed structures. The family name is usually the first level of plant classification discussed when talking about specific plants as pest or disease problems and management practices may be similar within a family. Family names always start with a capital letter and end in “aceae”. The family name for most of our common turfgrasses is Poaceae. For broadleaf weeds such as the English daisy (Bellis perennis), the family name is Asteraceae.

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Figure 10: The Plantain family, Plantaginaceae, includes narrow-leaved plantain (left), broad-leaved plantain (centre) and starweed (right). Photos NZSTI

Figure 11: The Daisy family, Asteraceae, includes the English daisy (left), Leptinella dioica (centre) and Leptinella maniototo (right). Photos: NZSTI

Figure 12: The Poaceae family includes most common warm season and cool season turf grasses such as Poa annua (left), Kikuyu (centre), tall fescue and ryegrass (right). Photos: NZSTI

Genus The genus level of the taxonomy places plants that have many attributes in common, in a smaller grouping within a family. Think of it as an immediate family rather than an extended family. The number of plants in a genus can range from a single species to many hundreds. Genus groups for cool season grasses include: ~ ~ ~ ~

Agrostis – bentgrasses and browntops Festuca – the fine fescues and tall fescue Lolium – ryegrasses Poa – bluegrasses, including Poa annua

Cynodon is a well-known genus of warm season grasses as it includes many couch species used for sports turf.

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Species A species is the basic group within the taxonomic system which contains same type of organisms. Individuals within a species share the same characteristics. One genus may have any number of species within it. As mentioned earlier, the same species, whether of plant or animal, might have several different common names around the world. So, each species is given a unique two-part scientific or Latin name to identify it. The name of the genus and the name of the species are combined to make the scientific name. For plants, the scientific name is also called the botanical name. We write scientific names a specific way: ~ The name is always put in italics when typed, or underlined when handwritten. ~ The genus (the first word in the scientific name) is always given a capital letter, while the species name (the second word in the scientific name) just starts with a small letter. For example, the botanical name for: ~ Kentucky bluegrass is Poa pratensis. This tells us that the plant’s genus is Poa and the species is pratensis. There is another common species within the Poa genus, Poa annua. ~ Browntop is Agrostis capillaris. The genus is Agrostis and the species is capillaris. ~ White clover is Trifolium repens. ~ Toad rush is Juncus bufonius.

Further variations Some plant species have further differences within them that are identified as a “variety”, “cultivar” or “hybrid”.

Variety Varieties are naturally occurring variations that have inheritable differences from the straight species. For example Festuca rubra has two common varieties:

~ Slender creeping red fescue, Festuca rubra var. litoralis ~ Strong creeping red fescue, Festuca rubra var. rubra Variety names should be written in the same way as species names using lower case letters and underlined or italics. The word variety can be shortened (as shown above), but should not be underlined or italicised.

Cultivar A cultivar is a variation which is purposely bred and cultivated, and so by definition they don’t occur naturally. Cultivars are bred to bring more desirable characteristics into a plant. For example, in turf this might include characteristics such as better pest or disease resistance, improved colour, or improved winter or summer performance. Some common turf cultivars are listed in the table below. Cultivar names are always capitalised and indicated by putting single quotation marks around them, or by using the abbreviation cv. For example: ~ Lolium perenne ‘Arena 1’ ~ Agrostis capillaris cv. Egmont.

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Table 2: Common turf cultivars found in New Zealand Species

Cultivars

Browntop

Egmont, Troy, Manor, Arrowtown

Creeping bentgrass

SR1119, Pencross, T1, Pure Destinction

Ryegrass

Centurion, SR4600, Arena, Spartacus, Coloseum

Tall fescue

Jackal, Carrawong, Siesta, Torpedo

Chewings fescue

Silhouette, SR51300, Calliope

kikuyu

Regal Staygreen, Whittet

Couch

Legend, Wintergreen, Agri-Dark, Princess

Red fescue

SR5210, Jasper 2

Carpet grass

Not applicable

Poa annua

True Putt

Hybrid A hybrid is a group of plants made by crossing two species or varieties. A hybrid is written by putting an x between the two parent species. For example, the hybrid from crossing Cynodon dactylon and C. transvaalensis can be written: ~ Cynodon dactylon x Cynodon transvaalensis, or ~ Cynodon dactylon x C. transvaalensis

Reading and writing the scientific names of plants There are lots of rules about how to write the scientific names of plants, and you won’t need to know all of them at this stage. However, it’s useful to understand these rules when you are reading about botany. Here are the basics that we are using at Level 3: ~ The plant’s family name always starts with a capital. ~ A plant’s scientific or Latin name is always put in italics when typed, or underlined when handwritten. For example, the scientific name for annual poa is Poa annua. ~ The genus (the first word in the scientific name) is always given a capital letter, while the species name (the second word in the scientific name) just starts with a small letter. ~ Some names are always given capitals (such as Cynodon, Kikuyu, and Kentucky bluegrass) because they are named after a place or person. ~ Where the names of several species of the same genus are used together in the same sentence or paragraph, after the first time, the genus name can be shortened to the first letter followed by a full stop. For example, in a paragraph about the different species of the genus Zoysia, the writer could refer to them as: Zoysia japonica, Z. matrella, and Z. tenuifolia. ~ A writer should refer to one species as “sp.” and two or more species as “spp.”  

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Cool and warm season grasses One of the most significant divisions of groups of plants is the separation into two different types of grasses based on climate. On the Botanical Taxonomy Chart, you can see that the Poaceae family of grasses divides into subfamilies of cool season grasses and warm season grasses. In New Zealand, we find grasses from both categories, but cool season grasses are the most common because of New Zealand’s temperate climate. “Temperate” means cooler than a tropical climate but not as cold and harsh as a polar climate. However, what counts as temperate is constantly evolving as climate changes occur. Warm season grasses are mainly found north of Hamilton and North Island coastal areas as they are best suited to the warmer climate and lack of frosts in these parts of New Zealand. Cool season grasses are found in all regions of the country.

Figure 13: Warm season grasses (in orange) in New Zealand are found mainly north of Hamilton, and in coastal areas all around the North Island, and in the west of Tasman Bay in the South Island. Cool season grasses are found throughout New Zealand. Graphic: Daniel Dalet1 1

Dalet, D, Map of warm season and cool season grasses in New Zealand. Retrieved from htto://d-maps.com BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Cool season grasses Cool season grasses are found in all regions of New Zealand. They grow best at temperatures of 16-24 degrees celsius (oC). Root growth will cease at approximately 27oC and shoot growth stops above 32oC.

Figure 14: Growth of cool season grasses by season. Graphic: Sprinkler Warehouse, Inc, 2007 Features of cool season grasses: ~ Cool season grasses have a medium-high water requirement and use about 20% more water than warm season grasses. ~ Cool season grasses enter dormancy (turn brown) if they don’t get enough water in dry periods (droughts) and could ultimately die. ~ Cool season grasses grow relatively well in shade compared to warm season grasses. ~ In warmer parts of New Zealand, cool season grasses perform well during winter and can be oversown into a warm season turf for the winter season. Cool season grasses are often referred to as C3 plants as the process of photosynthesis (the plant’s ability to make food using sunlight) produces three carbon atoms. The process of photosynthesis requires the stomata (pronounced stow-MAH-ta, tiny holes in a plant’s leaves) to open and close to allow gases (such as carbon dioxide and oxygen) to be absorbed and released by the plant. Water is also lost through these tiny openings. In cool season grasses, the stomata must stay open for photosynthesis to occur, which in their preferred cooler climates does not result in too much water loss for the plant. There are approximately 10 cool season grasses which are commonly used for sports turf in New Zealand. Table 3: Common cool season turfgrasses used in New Zealand. Common name

Botanical name

Kentucky bluegrass

Poa pratensis

Poa or poa annua

Poa annua

Perennial ryegrass

Lolium perenne

Tall fescue

Festuca arundinacea

Strong creeping red fescue

Festuca rubra

Slender creeping red fescue

Festuca rubra var. litoralis

Chewings fescue

Festuca nigrescens

Hard fescue

Festuca ovina var. duriuscula

Creeping bentgrass

Agrostis stolonifera

Browntop

Agrostis capillaris

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Warm season grasses Warm season grasses are adapted to warm, wet or semi-arid (semi-dry) conditions, so they are commonly found in countries close to the equator, and can grow in northern parts of New Zealand. They grow best in temperatures of 27-35oC, and are not well adapted to cold climates. Shoot growth typically stops at approximately 13-16oC and root growth at 10-16oC. Below 10oC warm season grasses usually become dormant and turn brown.

Figure 15: Growth of warm season grasses by season. Sprinkler Warehouse, Inc, 2007 Features of warm season grasses: ~ Warm season grasses have a low water requirement and use about 20% less water than cool season grasses. ~ Warm season grasses enter dormancy when temperatures cool and will turn brown. ~ Warm season grasses have don’t grow well in the shade compared to cool season grasses. ~ In warmer parts of New Zealand, warm season grasses can be oversown with cool season grasses to maintain year round performance. ~ The majority of warm season turfgrasses have a spreading/creeping growth habit which is a tremendous advantage as the turf is self-repairing if damaged. Warm season grasses are often referred to as C4 plants as the process of photosynthesis produces four carbon atoms. Unlike C3 plants, in order for photosynthesis to occur the stomata do not need to be open, which minimises too much water loss in warm climates. There are approximately six warm season grasses commonly used for sports turf in New Zealand. Table 4: Common warm season turfgrasses used in New Zealand Common Name(s) (country where this name is used)

Botanical name

St Augustinegrass (US) Buffalo grass (Australia & New Zealand)

Stenotaphrum secundatum

Narrow leaved carpet grass

Axonopus affinis

Kikuyu

Pennisetum longistylum var. clandestinum

Bermudagrass (US)

Cynodon dactylon

Common couch (Australia) Couch/Indian doab (New Zealand) South African Bermudagrass (US) South African couch (Australia) Transvaal doab (New Zealand)

Cynodon transvaalensis

Hybrid Bermudagrass (US) Hybrid couch (Australia and New Zealand)

C.dactylon X C. transvaalensis BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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2. Parts of a turfgrass plant Knowing the parts of a grass plant is helpful to identify different species. In turn, correctly identifying different turf species is essential for managing both desirable and undesirable plants. Like all plants, grasses are comprised of three main parts - leaves, stem and roots - and it is the modifications or variations of these parts which give each species its individual characteristics. As turfgrasses are mown short, identification can be difficult. Careful examination is often required and we need to focus on the most distinctive characteristics to allow us to make a positive identification. Flowers and seed heads are the most distinctive of all features to help identify the grass, but they are not always seen in sports turf.

Figure 16: External features of the grass plant. Graphic Kelvin13, n.d. 18

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Turfgrass leaves Turfgrass leaves typically consist of three parts: a leaf sheath, blade and collar area.

Figure 17: The veined and hairy leaf sheath of a couch plant. A leaf sheath is the part that surrounds the newly emerging stem or shoots. It is basically a modified petiole (pronounced “pee-tee-oll”, the stalk that connects the leaf blade to the stem). It may be compressed or rounded and the base may be swollen or coloured. For example, Cynodon dactylon (couch) has a leaf sheath which is rounded and short with fine green veins, and has 3-4mm hairs present at the junction of the blade and sheath. The leaf blade is the upper part of the leaf. Various leaf blade features can help to identify one grass species from another. The colour (such as light green or bluish-green), and the length and width of leaves can vary from one grass species to another. The leaf blade may also be smooth or covered with fine hairs, and be either glossy or dull (both on the upper and lower sides). We use some specific words to describe features of the leaf blade such as: ~ It can have ribs, which are raised lines running lengthways along the leaf. ~ A dip running along the centre of the top of the leaf is called a tramline. ~ A raised line running along the back of the leaf is called a keel. ~ The tip if the leaf may fold or curl together to form a hood.

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Figure 18: A comparison of the leaf blades of creeping bentgrass (left), Poa annua (centre), and browntop (right). Photo: NZSTI For example, Poa annua has a leaf blade 1-14 cm long which is soft to touch with a blunt tip that is often clearly hooded. The upper surface of the leaf blade has no ribs and indistinct central tram lines. The lower leaf surface is dull to glossy at the base with an indistinct keel at the tip.

Figure 19: Leaf blade of Poa annua showing the distinctive “tram lines” (left) and hooded tip (right). Photos: NZSTI The point where the leaf blade joins the leaf sheath is where the collar, ligule and auricles can be found. The collar is the area on the outer side of the leaf at the junction of the sheath and blade. The colour and texture of the collar can be different to the rest of the leaf.

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Figure 20: The collar joins the leaf sheath to the leaf blade. Photo: NZSTI The ligule is a small feature found on the inside of the leaf extending upward from the sheath. The ligule is a thin or rigid membranous (thin and flat, like a membrane) structure, or ring of hairs, which surrounds the shoot. Ligules can vary in size and shape. Some are serrated, others are long and pointed. You can see the ligules best if you pull the leaf back from the stem.

Figure 21: Distinct ligule on Agrostis stolonifera (creeping bentgrass) (left), compared to a very short ligule on Agrostis capillaris (browntop) (right). Photo: NZSTI BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Auricles are present in some grasses as claw-projections at the inside base of the blade. They clasp the stem and shoot. Auricles vary in size or may be absent altogether.

Figure 22: Prominent auricles on tall fescue A new leaf grows up through the centre of the shoot formed by the leaf sheath of older leaves. The new emerging leaf may be folded or rolled. Finally the blade emerges above the older leaves that surround it and unfolds or unrolls.

Figure 23: Examples of a rolled (left) and a folded (right) emerging leaf blade. (Photo: NZSTI)

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Turfgrass stems The stem of a grass plant consists of a series of nodes and internodes. The node is the usually solid and swollen part of the stem from which leaves are produced and attached. The internode is simply the section of stem between nodes.

Figure 24: Nodes on on Kikuyu plant. You can see shoots already growing from the first three nodes. Photo: NZSTI There are three main kinds of stems: ~ the crown ~ lateral stems (tillers, rhizomes and stolons) ~ flowering culms. The crown is a condensed stem with very short internode sections between the nodes. New leaves are formed from a growing point at the top of the crown. The crown’s growing point is completely enclosed within the base of the shoot above. A shoot is a stem and its leaves. The growing point produces stems, leaves and inflorescences (the flowering parts). On a grass plant, the growing point is located at or near the soil surface. The low growing point allows the plant to be frequently mown without destroying its ability to produce new growth.

Figure 25: The crown of a grass plant from which stem growth occurs. Photo NZSTI BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Axillary buds are located just above each node on the crown. These buds can produce lateral (lengthwise) stems in the form of tillers, rhizomes, stolons. ~ A tiller is the name given to every stem produced from the crown after the initial parent shoot grows from the seed. All grasses tiller (produce tillers) which gives turf its density. Turf grasses also produce new tillers to replace the old stems and leaves that die off after a year or so. A turf plant is considered perennial if it is capable of this continual replacement of tillers. ~ Stolons are stems that spread horizontally above the ground. Grasses that spread by stolons are described as stoloniferous. ~ In comparison, some grasses grow rhizomes, which are stems complete with nodes, internodes and scale-like leaves that grow horizontally beneath the soil surface. These plants are described as rhizomatous. Stolons and rhizomes both form roots and additional upright shoots at the nodes of the their stems, which become the growing points for these plants. Buffalo grass is an example of a grass that spreads by growing stolons; Kentucky bluegrass is an example of a grass that forms rhizomes. Some grasses, such as couch and Kikuyu, form both stolons and rhizomes.

Figure 26: Stolons spread horizontally above the ground, while rhizomes grow horizontally below the ground. Note the clear difference between the rhizome and the plant’s roots. Photo: NZSTI Grasses without a spreading habit are known as bunch grasses (e.g. ryegrass, tall fescue, poa annua). Bunch grasses are named as they do not spread much, because the growing points form only at the crown.

Figure 27: Perennial ryegrass is a good example of a bunch grass. Photo: NZSTI 24

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Turfgrass flowers At flowering, the growing point stops forming leaves and instead produces a culm, which is a flowering stem. The stem extends through the centre of the leaf sheaths to emerge in an inflorescence (a group of many flowers) at the top.

Figure 28: The flowering culms of three different turf species: ryegrass (left), tall fescue (centre) and browntop (right). Photo: NZSTI Turfgrasses such as Poa annua flower at very low cutting heights. Flowering often results in reduced turf density because the plant’s energy is put into producing flowers and seeds rather than more leaves. Sometimes the plant will even die following flowering, relying on its seeds to maintain the species.

Figure 29: Poa annua flowering. Photo: NZSTI BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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The basic unit of a flowering culm is a spikelet (see Figure 30). These are arranged in branching panicles (flower heads), in spike-like panicles, or in a single spike. Each spikelet contains one or more flowers.

Figure 30: A magnified view of a spikelet and the flowers it contains. Photo: NZSTI Like many plants, turfgrass flowers need to be pollinated to create fertile seeds. In a natural state (that is, when the flower heads are not mown regularly), cool season grasses reproduce by seeding. Warm season grasses commonly reproduce by vegetative means, by their spreading growth habits.

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Turfgrass roots As grasses are monocotyledons, they have a fibrous root system. Roots provide anchorage and support to the plant, while they also take up water and nutrients for survival. Grasses have two kinds of roots: ~ primary roots ~ secondary roots. The first short-lived root, formed at seed germination, is called the primary root (or seminal root). Secondary roots (or adventitious roots) soon replace the primary root as the seedling plant establishes itself. Secondary roots are formed in the first few nodes at the base of the stem and have a branched and fibrous nature. Secondary roots also form at nodes on the rhizome or stolon. Grass roots grow in a tapered shape, meaning there are more roots closer to the plants, and fewer roots at greater lengths. To develop a strong root system, the plant needs to have adequate light, carbon dioxide and its preferred air temperature, as well as water and nutrients via its root system. The roots themselves also need to have adequate oxygen in the rootzone for it to function effectively. A minimum amount of soil moisture is required for growth as roots will not enter dry soil “in search of water”, a common misbelief held by many people.

Figure 31: Examples of a turf plant’s tapering root system. There are more,shorter roots closer to the plant, and fewer longer roots at the bottom. Photo: NZSTI

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The depth that roots will penetrate depends on soil moisture, soil structure and the height of top growth. Almost as much of the grass plant lives in the soil as above the ground. Approximately a quarter to half of the root mass of a perennial grass dies and must be replaced with new growth each year. This means that they become important builders of soil and reservoirs (holders) of nutrients - which is why grasses contribute so much to soil fertility. However, this turnover of the plant tillers and roots is the major contributor to thatch and organic matter, which is a problem when in excess. The most significant soil physical condition affecting root growth is compaction: when the soil particles are pressed tightly together, limiting the movement of the air and water needed by the roots in the soil, and providing less space for new roots to develop. Roots do not easily force their way through the soil mass, but grow in cracks, fissures and less-compacted gaps in the soil. There can be a flush of root growth where plants suddenly find an area of less-compacted soil, such as at the side of a cricket pitch, or in holes left by aeration treatment.

Figure 32: Root flush down the side of a clay cricket pitch (left). Root flush down aeration holes in a thatchy sand profile. Photos: NZSTI On sand rootzones, commonly used in sports turf, the sand does not compact, but the pore spaces (holes) between sand grains can fill up with organic matter, resulting in similar problems to compaction.Roots may live up to two years dependent upon the grass species, climatic factors and soil conditions. Root death of cool-season grasses is greatest during heat stress and root growth of warm season grasses stops when soil temperature falls below 10-15 oC.

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3. Common desirable sports turf plants The common sports turf plants used in New Zealand are perennials which live for many years when not subject to too many stresses. Annual grasses are of little use because they produce a lot of seed as a survival tactic in times of stress. The exception is Poa annua which is a prevalent species in many golf greens and sports fields in New Zealand. In New Zealand, there are two species of cotula and one species of starweed used on bowling greens; a situation unique to this country. All three species are broad-leaved plants and have completely different management requirements to conventional turfgrasses - another reason why sports turf management is so specialised. Table 4 lists the main cool and warm season sports turf plants found in New Zealand against the type of sports they are used for. Fine sports turf refers to surfaces such as golf and bowling greens, tennis courts, croquet lawns, fairways, tees, cricket outfields and pitches, and ornamental lawns (often cut at 3-20mm). Coarse sports turf refers to surfaces such as winter sports fields, racetracks and areas of golf course rough (often cut at 30+mm). Table 5: The main cool and warm season turf plants found in New Zealand. Common name

Botanical name

Typical sports situation

~ Browntop ~ Creeping bent Fescues

Agrostis capillaris Agrostis stolonifera

Fine sports turf Fine sports turf

~ Chewings fescue ~ Strong creeping red fescue ~ Slender creeping red fescue ~ Hard fescue ~ Tall fescue Ryegrasses ~ Perennial ryegrass Bluegrasses

Festuca nigrescens Festuca rubra Festuca rubra var. litoralis Festuca ovina var. duriuscula Festuca arundinacea

Fine sports turf Fine sports turf Fine sports turf Coarse sports turf Coarse sports turf

Cool season Bentgrasses

~ Kentucky bluegrass ~ Poa annua Broadleaf species ~ Cotula dioica ~ Cotula maniototo ~ Starweed

Lolium perenne

Fine & coarse sports turf

Poa pratensis Poa annua

Fine & coarse sports turf Fine & coarse sports turf (bowling greens)

Leptinella dioica Leptinella maniototo Plantago triandra

Fine sports turf Fine sports turf Fine sports turf

Warm season Couch (Cynodon or Bermuda grass) ~ Indian doab ~ African or Transvaal doab ~ Hybrid Bermuda grass/ couch ~ ~ ~ ~

Kikuyu Buffalo grass Carpet grass Seashore paspalum

Cynodon dactylon Cynodon transvaalensis Cynodon transvaalensis X Cynodon dactylon Pennisetum clandestinum Stenotaphrum secundatum Axonopus affinis Paspalum notatum

Fine & coarse sports turf Fine sports turf Fine & coarse sports turf Fine & coarse sports turf Fine & coarse sports turf Fine & coarse sports turf Fine & coarse sports turf

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Cool season turfgrasses Browntops and Bentgrasses The Agrostis genus includes two common sports turf cool season species used for fine turf.

Browntop/Colonial bentgrass - Agrostis capillaris This species is commonly known as browntop in New Zealand but has several common names overseas, including colonial bentgrass and common bentgrass. It is predominantly used in New Zealand and the United Kingdom in golf and other fine turf situations. Leaf

Growth habit

~ Emerging leaf is rolled Browntop spreads by rhizomes. ~ leaf blades are short and narrow, tapering to the tip ~ leaf colour is dark green to bluish green ~ the upper blade surface has ribs which are slight with round tops ~ the lower blade surface is dull to slightly glossy

Ligule is very short, 0.5-1.5 mm, thin and blunt

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Browntop’s trailing stems (top) compared to the stolon of creeping bentgrass with roots (bottom).

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Other features

Creeping bentgrass - Agrostis stolonifera Creeping bentgrass is used throughout the world in closely mown, fine textured turf situations (down to 3mm). The common name comes from its vigorous creeping stolons growing along the surface. It looks like browntop but has a longer ligule, has stolons and is blue-green in colour. Creeping bentgrass demands a relatively high fertility level, particularly nitrogen. Because of this, thatch control techniques like verti-cutting are required regularly. Establishment is mostly done by seeding although plugs or turfing can be used. Leaf

Growth habit

Other features

~ the emerging leaf is rolled ~ leaf blades are short and narrow, ribs very regular, margins slightly rough ~ Colour is bright green to bluish green (bluer colouration than browntop)

It produces stolons to spread, which often have a reddish tinge.

It has a long, pointed ligule (24mm).

A creeping bentgrass sward.

Creeping bentgrass (lighter colour) in a sward of browntop (darker turf ).

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Fescues At this level, the goal is to identify the differences between tall fescue, the fine fescues, and other turf common turf grasses. Of the 100 or so fescue species, only a few are used as turfgrasses, and these are listed below. Of the fine fescues, the following are commonly used: ~ Chewings fescue, Festuca nigrescens ~ Strong creeping red fescue, Festuca rubra var. rubra ~ Slender creeping red fescue, Festuca rubra var. litoralis Some of the other fine fescues are not as common, or are rarely used: ~ Hard fescue, Festuca ovina var. duriuscula ~ Blue fescue, Festuca glauca ~ Sheeps/blue fescue, Festuca ovina var. glauca One further fescue species is commonly used as a turfgrass: ~ Tall fescue, Festuca arundinacea is unique amongst the turfgrass fescues as it has coarse leaves.

The fine fescues The fine fescues are characterised by their very fine bristle or needle-like leaves. It is very hard to separate Chewings fescue, red fescue and hard fescue. The key things to remember are that red fescue spreads by short rhizomes, whilst Chewings fescue and hard fescue are bunch-type grasses. In general, for the fine fescues: ~ ~ ~ ~ ~ ~ ~

Emerging leaf is folded Leaf width less than 1mm Blades dark to bluish green, long and narrow (bristle-like) with distinct keel Regular ribbed upper leaf blade with short bristles Lower surface slightly glossy Knoblike swellings in place of auricles Sheath - bright red veins with brownish outer sheath

Figure 33: Left to right: Fine fescue in a sward; the knob-like swellings instead of auricles; and the brownish outer sheath common to fine fescues.

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Leaf

Growth habit

Other features

Chewings fescue has light to dark green leaves (circled).

Bunch growth habit of Chewings fescue, which forms a denser turf than either creeping red fescue.

Chewings fescue ligule.

~ Strong creeping red fescue has ~ Strong creeping red fescue The ligule on a red fescue. dark green leaves has long spreading rhizomes. Less dense than slender, also ~ Slender creeping red fescue is less tolerant of close mowing. also dark green. Intolerant of wet conditions ~ Slender creeping red fescue has short slender rhizomes, but is slow to recover on bare areas.

Hard fescue has leaves greyish green to bluish green (circled), which are quite stiff and spiky to touch in comparison with the other fescues. Sheeps/blue fescue has blue-green leaves.

Hard fescue has a bunch growth habit, with growth described as whorled. Not adapted to close mowing (less than 50mm).

The ligule on a hard fescue.

Bunch growth habit. Tufted stiff On the plus side, it survives under leaves, and has not adapted to close extreme drought conditions, sandy mowing (minimum cutting height soils. 30mm). BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Tall fescue Unlike the fine fescues, tall fescue has both auricles and larger leaves. The auricles are tan in colour and covered with stiff hairs. Tall fescue provides a coarse turf which is mainly used on lawns but may be used in sports fields. While tall fescue is wear tolerant it is unfortunately very slow to recover once damaged. Photo on right: Tall fescue (left) has some similarities with ryegrass (right), but unlike ryegrass, tall fescue lacks a distinct ‘keel’ on the back of the leaf blade, and has wider flatter leaves with more prominent ribs.

Leaf

Growth habit

~ Blades green to dark green, wide and flat with indistinct keel ~ Moderately ribbed upper leaf blade, variable in height, width and distance apart.

Tall fescue has a bunch-type growth ~ Auricles with very short, bristly habit which can be strongly tufted hairs which continue along the after wear (except for a couple of base of the margin. cultivars (eg Torpedo, which spreads ~ Hairs on the margin of the leaf by short rhizomes). blade give a rough feel.

~ Emerging leaf is rolled ~ Leaf blade is about 4mm wide at a cutting height of 20mm ~ Lower surface glossy and keel indistinct ~ Sheath can be smooth or rough, often with indistinct cross veins. Base often purple.

Tall fescue turf.

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Other features

Ligule up to 2mm long, membranous, firm, greenish, not visible in side view

Ryegrasses Ryegrasses (Lolium spp.) have a bunch-type growth habit. Being established by seed which has a quick germination time and vigorous seedling growth, ryegrass is suitable for where rapid ground cover is desired. On the downside, ryegrasses are intolerant of temperature extremes, drought, and certain diseases.

Perennial ryegrass - Lolium perenne Perennial ryegrass is best adapted to cool, moist conditions and is widely used on sportsfields, golf courses (tees, fairways), race tracks and home lawns. Because of its rapid germination and vigorous seedling growth, ryegrass is often used for overseeding warm season turf for winter play. Ryegrass is quite wear-tolerant. Many improved turf-type ryegrass cultivars are available. Recent breeding has seen the release of a couple of creeping ryegrass cultivars such as CSI Ryegrass. Leaf

Growth habit

Other features

~ Emerging leaf is folded ~ Blades bright to dark green in colour ~ Moderately ribbed upper surface of blade. Very glossy lower surface of blade ~ Distinct keel present

Bunch type growth habit.

~ Ligule is short, translucent and membranous. ~ Very small auricles

Sheath base almost always reddish in colour, although much less obvious in the more recent cultivars.

A ryegrass sward.

A ryegrass flowering culm.

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Poa species The Poa genus has species which are also known as bluegrasses, and it includes several species that are important as turfgrasses. These species vary significantly from one another, but they all have certain features in common: ~ ~ ~ ~

Young leaf blades are folded as they emerge from the enclosing sheaths of older leaves Boat-shaped leaf tip (the leaf blade gathers toward the tip to form a bow like a boat) Smooth leaf blades with parallel translucent lines on either side of the central midrib (tramline) Absence of auricles and membranous ligules

Poa annua This species is commonly known as Poa annua in New Zealand but has several common names overseas including annual poa, annual meadowgrass and winter grass. Poa annua forms a very dense, fine-textured turf. Although rarely planted intentionally, it is frequently the major component of irrigated surfaces such as golf course greens, tees, fairways and sportsfields. Poa annua is a strong weed competitor and volunteer grass as it establishes freely and rapidly from seed, and is a prolific seed producer forming a high seedload in the ground from which it can quickly germinate. Tolerant of over irrigated, poorly drained/compacted soils and shaded conditions, Poa annua often performs better than the planted turfgrass. However, its susceptibility to disease and poor tolerance of heat/drought stress makes it an undesirable “weed” throughout most of the world. Leaf

Growth habit

~ Emerging leaf is folded ~ Blades light green to yellowish green ~ Upper leaf surface: ribs absent ~ Lower leaf surface dull, rounded with indistinct keel.

Poa annua has a bunch-type ~ Ligule 2-5mm long, growth habit, and is a prolific membranous, milky white, seeder, often under mowing height. slightly pointed ~ No auricles ~ Sheath compressed but rounded at base.

~ Blade soft, often crinkled when young, hooded leaf tip ~ Central tramline.

Poa annua growing in the midst of ryegrass, showing its light green colour and many seedheads.

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Flower / seedhead

Kentucky bluegrass - Poa pratensis Kentucky bluegrass is similar to perennial ryegrass in appearance, although typically a darker bluish-green in colour. Unlike perennial ryegrass which has a bunch-type growth habit, Kentucky bluegrass has a strong spreading rhizomatous growth habit. Kentucky bluegrass requires moderate to high fertility and irrigation during drought periods. In humid climates, leaf spot disease pathogens are quite troublesome and it suffers badly from rust in the autumn in NZ. Kentucky bluegrass is more heat and cold tolerant than perennial ryegrass and is generally found growing in the inland drier areas of New Zealand (Central Plateau and Central Otago). Leaf

Growth habit

Flower / seedhead

~ Emerging leaf is folded ~ Leaf blade has distinct tramlines.

Rhizomatous growth habit.

Ligule short (0.5-1mm), membranous green/white.

The blueish green leaves of Kentucky bluegrass stand out amidst browntop.

~ Stiff, erect, dark green to bluish green leaf blade ~ Leaf blade has hooded tip.

A seedhead of Kentucky bluegrass.

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Warm season turfgrasses Couch (Cynodon) species There is tremendous variability within the Cynodon genus, including dwarf and tall varieties, prostrate and upright growth habits, and fine and coarse-textured turf.

Couch (Cynodon) species Cynodon is the most widely used of all the warm season grasses. All Cynodons have both a strong rhizomatous and stoloniferous growth habit. They have excellent drought and wear tolerance.

Figure 34: Different couch species and varieties compared to common couch (top) have leaf textures and internode length. The size of stolons will also vary between couch types. Key identifying features of Cynodon spp: ~ ~ ~ ~ ~

Emerging leaf rolled Blades short and stiff Stoloniferous or rhizomatous growth habit Long hairs at junction of blade sheath Ligule 0.5mm long and hairy

Over the past ten years interest has increased in the development of seed-propagated Cynodon. Turf establishment by seeding is a cheap and convenient method when compared against vegetative propagation methods (eg. plugging, turfing, sprigging). ‘Arizona common’ Cynodon seed has been available for many years. The turf is relatively coarse with excessive seed head formation that detracts from the overall appearance. Plant breeders have released new seeded lines over the past few years. Although the new cultivars are significantly better than ‘Arizona common’ they generally are not as dense or as fine as the vegetative selections of common and hybrid Cynodon. Only one commercially available seeded Cynodon ‘Princess’ compares favourably with the vegetative selections of common and hybrid Cynodon. 38

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Common couch - Cynodon dactylon Common couch is a medium-textured warm season grass. Leaf

Growth habit

Flower / seedhead

The wide, shorter blades of common couch stand out from browntop.

Stolon growth.

~ Long hairs at junction of blade sheath ~ Ligule 0.5mm long and hairy.

Couch in a semi-dormant state and going brown.

Rhizome growth.

Couch seedheads.

Transvaal doab - Cynodon transvaalensis African or Transvaal couch (Bermudagrass, Cynodon), has the same distinguishing features as common Cynodon except that the turf has a very upright growth habit and the leaf blade is noticeably finer with a lighter green colour. African couch typically has a higher demand for water, nutrients, and greater thatch production than common Cynodon.

Hybrid couch - C.dactylon x C. transvaalensis Breeding and selection work has produced hybrid Cynodon (C.dactylon x C. transvaalensis). All are sterile and do not produce viable seed. Hybrid Cynodon can only be propagated vegetatively. Improved hybrid Cynodon has several advantages over common Cynodon - strong lateral spreading growth habit, greater wear ability and greater tolerance of close mowing. Hybrid Cynodon is typically finer than common Cynodon having the fine textured characteristic of African couch as one of its parents. Along with the finer texture, hybrids also require more water and nutrients than common Cynodon. Thatch production is also higher.

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Other warm season turfgrasses Buffalo Grass / St. Augustinegrass - Stenotaphrum secundatum Native to the West Indies, Buffalo grass is a coarse-textured (6 - 8mm leaf width), vigorous, fast spreading, stoloniferous grass. It has a tendency to become thatchy when heavily fertilised. Considered the least cold tolerant of the warm season grasses, it is however, very salt tolerant, and is adapted to moist climates and coastal sands. Buffalo grass is suitable for areas such as fairways and tees, particularly if shade is a problem, but it does have low wear tolerance. New varieties have the improved characteristics of deep green colour, drought tolerant and a finer leaf texture. It can be established using plugs, stolons or turfing (known to Americans as sod). Leaf

Growth habit

Stoloniferous growth habit, with ~ Emerging leaf is folded distinctive dark-red-coloured ~ Blade greyish to bluish green, stolons. with wide, very flattened straplike blades and compressed sheaths. Blade splits when flattened. Few long hairs on margins at junction of blade and sheath. ~ Margins rough ~ Upper blade surface: ribs absent, Lower surface: moderately glossy, hairless, darker green than upper surface, sharp keel ~ Sheath - broad with fine, alternating green and white stripes, often with a reddish/ brown tinge.

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Flower / seedhead

Ligule - less than 0.5mm long with an inconspicuous fringe of hairs that can only be seen from above.

Narrow-leaved carpetgrass - Axonopus affinis Carpetgrass is a low and slow growing, relatively coarse-textured turfgrass with an extended period of seedhead production. It is used in low maintenance, general purpose turf situations. It requires little fertiliser and infrequent mowing. It performs well in wet, shady, and acidic soils (pH range 4.5 - 6.5). Carpetgrass looks similar to buffalo grass and blends in well with centipedegrass. Carpetgrass has poor cold, drought, and wear tolerance. Optimum growing conditions are full sunlight with temperatures averaging between 16 - 32 degrees centigrade. Establishment is by seed or sprigging. Leaf

Growth habit

Flower / seedhead

~ Emerging leaf is folded Stoloniferous growth habit often with reddish tinge. ~ Blades yellow to bluish green. Flat or folded, short and narrow with a blunt tip. Margins smooth ~ Upper leaf blade: ribs absent. A few 2-4mm hairs on margin near blade base. Lower surface slightly glossy. Distinct, dark lines near blade base. ~ Keel distinct and smooth

Sheath: strongly compressed, keeled, margins translucent and membranous with fine hairs.

~ Ligule: up to 1mm long, membranous, fringed with very short hairs. Creamy white. ~ Auricles absent.

Carpetgrass is low-growing and relatively coarse-textured, with an extended period of seedhead production.

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Kikuyu - Pennisetum longistylum var. clandestinum A native of eastern and central Africa at elevations of 1680 - 2700m, Kikuyu is well adapted to a mild, humid climate (20 - 35oC) and is relatively cold tolerant. Suited to well-drained, moderate to high fertility soils. Kikuyu has a coarse texture and light green colour. With thick rhizomes and stolons (5 - 8mm), it has an aggressive growth habit, and when planted next to other turfgrasses it can be very invasive and difficult to control. Thatch production is high and regular scarifying is needed to reduce sponginess. It can be established using rhizomes, stolons, turf, and seed. Leaf

Growth habit

Flower / seedhead

~ Emerging leaf folded. ~ Leaf blade hairy. Green to yellowish green in colour.

Kikuyu has both a stoloniferous and rhizomatous growth habit.

~ Ligule 2-3mm long fringe of distinct hairs at base of blade.

Despite its coarse texture, Kikuyu can form a dense sward.

Kikuyu stolons.

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Broadleaf turf plants Cotula (Leptinella) species Leptinella species (Cotula) are low growing native plants. Leptinella maniototo is more common in inland regions and Leptinella dioica comes from coastal areas. Both can be used alone or as a mixture in bowling greens in New Zealand . Both can produce flowers, have a fibrous root system, and have stolons that can spread into bare or damaged areas. Both species can change the colour of their leaves with the amount of growth typically dictated by the temperature, nitrogen and soil moisture.

Maniototo - Leptinella maniototo The Maniototo species is unusual in that it has a different leaf form for summer and winter: Plants produce seed-like structures which are called bulbils in winter (June-July) that can be harvested and used for repairing bare areas or re-sowing a new green. Leaf

Growth habit

Other features

The summer leaf form is green to brown-green, narrow, and heavily lobed (feathered).

Leptinella maniototo spreads into bare or damaged areas by stolons.

Bulbils under magnification.

The winter leaf form that is a narrow, Maniototo can also look brownish Leptinella maniototo bulbils grass-like leaf which is quite distinct when growing slowly (growth in growing. from the summer leaf form. the left), but greener when growing faster, as here after an application of nitrogen (growth on the right).

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Dioica - Leptinella dioica The dioica species have some variation but typically have fleshy, green-brown-green, heavily lobed leaves tapering to the base of the leaf. This species does not change its leaf form like Leptinella maniototo does. L. dioica is less susceptible to disease than L. maniototo. Leaf

Growth habit

Leptinella dioca has fleshy, greenbrown, heavily lobed leaves tapering to the base of the leaf.

Leptinella dioica can also spread into bare or damaged areas by stolons.

Leaf samples from L. dioica.

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Starweed Starweed - Plantago triandra Starweed produces colonies of small circular plants with hairy, raised transverse ridges on the usually toothed, often black blotched leaves. It has tiny insignificant white flowers. Starweed takes its name from the pointed leaves arranged in a start shape. It has a rosette-type growth habit with a fibrous root system and spreads by seed. Leaf

Growth habit

Other features

Starweed produces colonies of small circular plants with hairy, raised transverse ridges on the usually toothed, often black blotched leaves.

Starweed’s rosette type growth habit (cut in half ), showing the crown of the plant, fibrous root system and an emerging seedhead coming out from the left of the plant, with a yellowish tip.

Starweed has tiny insignificant white flowers, but the small seedheads are visible across a sward of starweed. This species spreads by seed.

Tightly-packed starweed in a bowling green.

Starweed emerging in a turfgrass area.

Starweed seedlings having emerged from the seedcase.

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4. Managing sports turf plants Turf-based sports surfaces are established using an appropriate plant species and maintained in such a way to provide the specific playing surface performance requirements of a particular sport. From a purely botanical perspective, sports turf surfaces are very artificial.

The demands of sport Sports turf in general is subject to high levels of use compared to agricultural or horticultural practices. This can lead to problems such as soil compaction, soil structure damage, reduced infiltration and loss of turf cover that will result in the turf not being able to be played on. Golf and bowling greens require tolerances for surface levels far tighter than are found in any other land-based industry. Grasses that grow naturally to several hundred millimetres in height in the absence of mowing or grazing are artificially bred so that they can tolerate a cutting height of only 3-4mm or less. Users of these greens then expect this surface to provide smooth putting for 12 uninterrupted months of the year. Sports like rugby and soccer place additional stresses on natural turf surfaces. Not only do these sports cause tearing and crushing of turf plants, but the action of players also causes compaction and smearing of the rootzone. Most games take place during the winter months when the rootzone is wet and when grass growth is virtually dormant because of low temperatures.

Figure 35: Winter sports such as rugby can cause a lot of damage to the plants and rootzone of a turf area. Horse racing is even more destructive with large divots of turf plants and rootzone being displaced by horses galloping at speeds of up to 50km/h. This can create a very uneven surface that needs to be reinstated in between race meetings. Cricket represents a particularly artificial situation. Here, everything is done to the turf plant and rootzone that is the complete opposite of good soil and plant management practices. The cricket pitch is first saturated and then rolled as it dries in order to get maximum compaction. The turf plant is pressed into the surface by more rolling, a process that causes substantial bruising of the leaves.

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Figure 36: A cricket pitch represents the complete opposite of usual good soil and plant management practices, in providing acceptable surface performance to meet the needs of the sport. Photo: NZSTI Many facilities are also multi-use and are used all year round which limits turf recovery, and renovation practices that can be undertaken. The turf environment is also subject to losses of nutrients from the soil due to the removal of grass clippings, where in agriculture there is greater return of nutrients. This creates a greater need for fertiliser. In many sports turf areas, efforts are also made to kill off the biological component of the soil. For example, earthworms are usually suppressed on golf and bowling greens in order to maintain smooth playing surfaces, and in sports fields to minimise both surface sealing and soil contamination especially in sand constructed rootzones. The virtually sterile nature of many sports turf rootzones requires a different, generally more intensive form of management compared with agriculture and horticulture. The needs of different sports can often be at conflict with the biological needs of the plants making up the turf, yet at the same time promoting good plant health is important to ensure plant survival each year. The challenge for turf managers is to balance the requirements of the plant and the turf surface with the expectations of users so that: ~ the sports turf area is able to support the level of use it receives, and ~ the sports turf area is used enough times to make the investment in its construction and maintenance financially viable.

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Turf plant growth and development Photosynthesis Photosynthesis is the process where plants make food - and therefore get their energy for growth - from sunlight, air and water. Sunlight provides energy which is absorbed by a green-coloured substance called chlorophyll, held inside the leaf cells. Chlorophyll gives leaves their green colour. Carbon dioxide (CO2), is absorbed by the plant from the air through stomata, tiny holes in the plant’s leaves. Water (H2O), is drawn up from the soil into the plant by its roots. Water and carbon dioxide undergo a chemical reaction using the energy produced by sunlight and combine to produce: ~ carbohydrates (C6H12O6). which provide fuel for the plant’s growth, and ~ oxygen (O2) which is released back into the atmosphere.

Figure 37: Photosynthesis is the process where plants take carbon dioxide from the air and water from the soil, and using energy from sunlight, convert it to carbohydrates for food, and oxygen, which is released back into the air.

Natural adaptations Natural selection is the process where plants or animals with specific features tend to survive and reproduce better in certain environments that they are naturally adapted to. The plants or animals that don’t have this feature will not reproduce as much and can eventually die out. Natural selection has led to turf plants having natural adaptations: features that allow some species to grow better in certain environments, such as in drier climates or in soils with lower nutrient levels. The diagram below summarises the natural adaptations of some of the more important cool season turf plants to soil fertility, soil moisture levels and soil pH.

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Figure 38: Natural adaptations of cool season grasses to soil fertility levels, soil pH and moisture levels. Shildrick, 1989, p. 60. Therefore, the first option to managing turf well is to choose the turf species that is best suited to your sports venue’s natural environment and the demands of the sports that will be played there. (However, this is often a decision that has been made previously, and many turf managers will not be in a position to change the main species used.) See the section titled The growing environment (after Cultivars, below) for more examples of turf species with different natural adaptations that make them more (or less) suited for different environments and sports turf uses.

Cultivars However, sometimes natural adaptations in turfgrasses don’t develop quickly enough, or for every feature that a turf manager might want. As we’ve detailed in Chapter 1, a cultivar is a variation which is purposely bred and cultivated to bring more desirable characteristics into a plant. In a sports turf context, cultivars can be bred to enhance existing desirable features, or to improve a weakness. Features such as colour, wear ability, hardiness at low temperatures, disease/pest resistance or desirable growth habits can be bred into a new cultivar. However, cultivated varieties also have disadvantages; while one or more features may be improved, they can also have other less-desirable features, compared to the original species or to other cultivars of the species. It is important to research the full range of features of a cultivar you are considering using at your venue.

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Table 6: Comparative characteristics of five Cynodon cultivars. Cultivar ‘Wintergreen’

‘Santa Ana’

Characteristics ~ Semi dwarf growth habit. Fine to medium texture and very dense growth. ~ High seed head production. ~ High wear tolerance. ~ Selected for tolerance to pollution (California). ~ Blue-green colour. ~ Fine to medium texture. ~ High seed head production. ~ High wear tolerance.

Adaptation ~ Spring dead spot disease less troublesome compared to hybrids. ~ Improved winter colour. ~ Performs well on a range of soils. ~ Improved winter colour. Moderate to high rate of thatch production. ~ With the use of a rotary mower, mowing quality is very poor.

Parentage Common (Cynodon dactylon)

Hybrid (C. dactylon X C. transvaalensis)

‘Tifgreen’ (328) & ‘Tifgreen II’

~ Fine leaf texture. ~ Excellent spring recovery characteristics. ~ Lighter colour, more upright and fine-leaf texture than Tifdwarf. ~ High wear tolerance.

~ Preferred mowing height Hybrid 6-12mm. (C. dactylon X C. ~ Poor low temperature colour transvaalensis) retention, but unlike Tifdwarf does not turn purple during winter. ~ High thatch production if mown high.

‘Tifdwarf’

~ Very short internode. ~ Very low growing (dwarf growth habit). ~ A mutation of Tifgreen. ~ Very high wear tolerance. ~ Wider leaf blade than Tifgreen. ~ Vigorous, upright growth habit. ~ High wear tolerance. ~ High seed head production.

~ Intolerant of wide temperature fluctuations. ~ Darker green than Tifgreen.

Hybrid

~ Better shade tolerance compared with many other common or hybrid cultivars. ~ Preferred mowing height 12-25mm. ~ High thatch production if over fertilised and watered.

Hybrid

‘Tifway’ (419 or Sportsway) & ‘Tifway II’

(C. dactylon X C. transvaalensis)

(C. dactylon X C. transvaalensis)

There is an increasing range of Couch varieties and selections that are available in New Zealand, that have intermediate properties to those discussed above. Some cultivars/selections include Agri-Dark, Legend, Eden Park etc.

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The growing environment As discussed above, in some cases we can select a turf species best suited to our particular sports turf growing environment, including the use the turf gets from players. If we can’t select the species, the next best option is to manage the conditions of the growing environment to suit the turf species that we have. There are five main environmental factors that affect the growth and development of desirable sports turf plants. These are: ~ ~ ~ ~ ~

soil moisture soil nutrients (fertility) the amount and type of light plants receive the temperature of the air and soil soil pH (acid/alkaline level).

To varying degrees the turf manager has the ability to influence all of these environmental factors, which are discussed in more detail below. There are also turf maintenance practices necessary to sports turf that have an effect on turf plant growth and development, such as mowing.

Soil moisture How a plant species responds to different soil moisture levels can affect its ability to provide acceptable quality sports turf. Turf plants vary in their requirements for water. Warm season grasses have a much lower requirement for water over the summer because of their natural adaptation to a warmer climate. Cool season grasses are adapted to grow in cooler climates, so generally require irrigation over the summer months to maintain healthy growth. Table 7: Water requirement differences between turf species. Turf plants

Warm or cool season

Tolerance of low soil moisture levels Excellent

Water requirements

~ Couch ~ Kikuyu ~ Carpet grass

Warm

Tall fescue Cool Fine fescue Kentucky bluegrass Cool Browntop Creeping bentgrass (A.stolonifera var. palustris) ~ Perennial ryegrass Cool ~ Starweed (bowling greens) ~ Cotula species (dioica, maniototo) (bowling greens)

Good

Low-moderate

Good

Moderate

Fair

Moderate-high

Poa annua

Poor

High

~ ~ ~ ~ ~

Cool

Vefry low

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Drought tolerance is the ability of the turf plant to survive a long time with low soil moisture. There are three different ways that turf plants can react to drought conditions: 1. Plants produce seed and die. The seeds germinate and new plants will grow as soon as soil moisture increases in the autumn. Poa annua is a good example of this. 2. Plants go dormant. They usually turn brown but restart green growth once soil moisture increases in the autumn. Browntop is one of several cool-season species that become dormant in dry conditions. 3. Plants will tolerate the drought and stay green. Couch and kikuyu both have excellent drought tolerance.

Figure 39: Poa, rye and browntop (making up the rough to the right) have low drought tolerance, whereas couch (used for the fairway on the left) has high drought tolerance and is still green. Photo: NZSTI Table 8: Drought tolerance characteristics of some common turf plant species. Emmons & Rossi, 2016 Drought tolerance Excellent

Turf plant species ~ Couch (Cynodon dactylon) ~ Kikuyu (Pennisetum clandestinum) ~ Zoysia grass (Zoysia spp.)

Very Good

~ Fine fescues (Festuca spp.) ~ Tall fescue (Festuca arundinacea)

Good

~ Kentucky bluegrass (Poa pratensis)

Fair

~ Perennial ryegrass (Lolium perenne) ~ Buffalo grass (Stenotaphrum secundatum)

Poor

~ ~ ~ ~ ~ ~ ~

Annual ryegrass (Lolium multiflorum) Browntop (Agrostis capillaris) Carpetgrass (Agrostis stolonifera) Creeping bentgrass (Agrostis stolonifera) Poa annua (annual poa) Cotula species (Leptinella spp.) Starweed (Plantago spp.)

Drought recovery is the ability to recover from prolonged drought. Couch (Cynodon dactylon) and tall fescue (Festuca arundinacea) can recover quickly from prolonged drought. Bentgrass (Agrostis spp.) will recover at a slower rate while (Poa annua is unlikely to recover from prolonged drought as it will generally set seed and die. Warm season grass species use less water than cool season grass species. This is due to their plant physiology enabling lower water use rates and high drought tolerance mechanisms. Warm season turfgrasses grow through the summer even with minimal water, but their growth will stop during the winter. 52

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Nutrients Turf plants need nutrients from the soil to grow, and so soil fertility is important in maintaining healthy turf. Soil fertility can also have a significant influence on the makeup of turf species in a sward. It is important to understand how some species can be encouraged or discouraged by different fertiliser applications.

Nitrogen Nitrogen is needed in the greatest amounts by the turf plant. The plant’s responses to nitrogen are: ~ ~ ~ ~

faster growth, including an increase in tiller production, leaf number and leaf size greener colour the increased turf density helps the turf sward compete against weed invasion A moderate amount of nitrogen is also good to reduce some diseases (for example, red thread and dollar spot).

However, a high nitrogen programme can result in: ~ shoot growth at the cost of root growth. Poor root development weakens the plant, particularly when in a stressful environment, for example, in low light. ~ soft, succulent tissue. This “soft” growth is vulnerable to diseases, and is less wear resistant. ~ reduced heat and cold tolerance. Different turf species require differing amounts of nitrogen to grow well. The table below outlines the basic nitrogen requirements of some common turf plants. Table 9: Nitrogen requirements of some common turf plant species Nitrogen requirements High

Turf plant species ~ Kentucky bluegrass (Poa pratensis) ~ Tall fescue (Festuca arundinacea) ~ Perennial ryegrass (Lolium perenne)

Medium

~ Creeping bentgrass (Agrostis stolonifera) ~ Couch grass (Cynodon dactylon)

Low

~ ~ ~ ~ ~ ~ ~ ~ ~

Carpet grass (Axonopus affinis) Chewings fescue (Festuca nigrescens) Red fescue (Festuca rubra) Browntop (Agrostis capillaris) Cotula (Leptinella spp.) Starweed (Plantago sp.) Buffalo grass (Stenotaphrum secundatum) Kikuyu (Pennisetum clandestinum) Velvet bentgrass (Agrostis canina)

Bentgrasses (Agrostis spp.) tend to be more responsive to nitrogen, whereas the fine fescues are more tolerant of lower amounts of nitrogen. This makes it quite difficult to maintain an equal mix of fescue/bentgrass in an established sward as the bentgrass will often take over well fed and watered conditions. In established turfgrass swards, fine fescues are rarely dominant. The overwhelming success of Poa annua in our sports turf surfaces is associated with its growth response to high soil fertility, plenty of water and its amazing ability to spread and set seed virtually throughout the year. Its success as a turf plant is a result of it being able to adapt to and exploit a wide range of ecological conditions. For example, bare, compacted areas which are well-fertilised and watered provide ideal conditions for Poa annua establishment, even if the area is oversown with Agrostis spp.

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Phosphorus and Potassium Phosphorus and potassium are also important elements for plant growth and development in all turf plant species. Both work with nitrogen to enhance nutrient responses (i.e. when nitrogen is deficient the response to phosphorus and potassium is lessened). ~ Phosphorus is important for tiller development in new turf and root development. ~ Potassium is important in disease resistance, turf wear ability and cold hardiness.

Figure 40: The basic role of nutrients in turf plants and their effect on plant growth and resilience.

Light Plants must have sufficient light to carry out the process of photosynthesis to provide enough food reserves to grow. Seasonal climates away from the equator, like in New Zealand, have longer days in summer and shorter days in winter (seasonal varying day length). The strength or intensity of light also changes with the season (seasonal light intensity). The sun is lowest on the horizon during winter which makes the day length shorter and the light intensity lower. The growth of warm season grasses declines very rapidly with shorter daylight hours, and optimum growth of warm season grasses occurs when day is greater than 13 hours. Under low light conditions: ~ leaves become more spindly (upright and longer) with a longer internode length, in an effort to better capture sunlight ~ leaves become narrower ~ the turf is more open and less dense as fewer leaves are produced from tillering ~ thinner turf is more likely to wear out ~ recovery from injury is slower ~ root growth is reduced and can be even more seriously affected than shoot growth ~ flowering is also held back.

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Figure 41: Long and spindly Kikuyu growth in low light conditions: Photo: NZSTI Morning shade from trees and buildings is worse than afternoon shade, because morning sun helps dry the turf surface which reduces algae, diseases, warms the soil and provides the brightest light. This is especially important in colder climates but also has an effect in tropical or sub-tropical climates where regular afternoon cloud reduces light levels. Turf growing in shade caused by trees and shrubs suffers not only reduced light but also leads to competition for nutrients and water by the larger plants, and lower soil temperatures. Grass in heavily shaded areas requires only one-half to two-thirds as much nitrogen fertiliser as turf in full sun because of its lower growth rate. This will also help to reduce disease. Turf growing in the shade loses significantly less water compared to turf growing in full sun. Turfgrasses show varying tolerances to low light. However, no plant will grow in full shade as some sunlight is required for photosynthesis to occur. Warm season grasses are generally less tolerant of shading than cool season grasses. Warm season grasses are adapted to grow using a lot of sunlight, and generally have a faster growth rate because of this. Cynodon spp. has poor shade tolerance. This is especially true for closely mown Cynodon spp. (eg, golf and bowling greens, cricket pitches). Close mowing reduces the leaf area capturing sunlight for photosynthesis. Cool season grasses generally require a minimum of 6-8 hours full sunlight per day year-round. Table 10: Relative shade tolerances of some common cool and warm season turf plants in their respective regions of adaptation (Beard, 1973). Shade tolerance Excellent

Good

Moderate

Poor

Turf plant species ~ Hard fescue (Festuca ovina var. duriuscula) ~ Red fescue (Festuca rubra) ~ Chewings fescue (Festuca nigrescens) ~ Buffalo grass (Stenotaphum secundatum) ~ FBrowntop (Agrostis capillaris) ~ Creeping bentgrass (Agrostis stolonifera) ~ Tall fescue (Festuca arundinacea) ~ Perennial ryegrass (Lolium perenne) ~ Cotula (Leptinella spp.) ~ Starweed (Plantago sp.) ~ Carpet grass (Axonopus affinis) ~ Kikuyu (Pennisetum clandestinum) ~ Kentucky bluegrass (Poa pratensis) ~ Couch (Cynodon dactylon) BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Turf management solutions to turf growing in shade or low light include: ~ Where possible remove the cause of the shade. For example, prune or remove trees and shrubs. ~ Select more shade tolerant grasses. ~ Mow the turf at a higher level to maximise leaf area for photosynthesis (for example, a 1.5 - 2.5cm higher cut) ~ Remove clippings to prevent further shading. Turf plant shading is a challenge in the development of covered stadia. The engineering of such stadia is often not focused on the needs of the turf but centered on locational and people needs, resulting in significant shading and reduced photosynthesis. The Forsyth Barr Stadium in Dunedin was a first of its kind in New Zealand, in that the needs of the turf was a key focus in the stadium design, resulting in significant increased light levels available to the turf.

In most cases though, the stadium has already been built, so the growth needs of the turf have had to be addressed another way. Use of growth lights is common in low-light stadia. Growth lights differ from lighting towers, in that they emit light in the photosynthetically active radiation (PAR) range, (see Figure 56) that plants need for photosynthesis. Flood lighting, on the other hand produces light that is most useful for the human eye, but does not aid plant growth.

Figure 42: A large growth lighting unit in a stadium (left), and although clearly visible to the human eye, the light emitted by these floodlights provides very little PAR light that the turf needs to produce food through photosynthesis; a reading of 2 mol m-2sec−1 is very low. Photos: NZSTI

Figure 43: The range of light visible to the human eye (left), compared with the range of light that plants use for photosynthesis (right).

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Temperature has a major influence on turf plant growth and development. For both cool and warm season grasses, the temperature range for root growth is lower than for shoot growth. This means that roots prefer slightly cooler soil temperatures than the air temperature suited to shoot growth. Cool season grasses prefer an air temperature of between 16-24°C, but can survive when the air temperature is 4°C and the soil temperatures reaches as low as 0°C. They are unsuitable in places where the air temperature is higher than 32°C. Warm season turfgrasses are particularly sensitive to cold temperatures. They prefer an air temperature of at least 27°C, and can survive in temperatures up to 50°C. Their roots need a soil temperature of at least 10°C to grow. However, Cotula species and starweed are able to adapt to many soil and climatic conditions, from alpine bogs to coastal estuaries with air temperatures ranging from -10°C to 40°C. Table 11: Effect of temperature on shoot and root growth of warm and cool season turfgrasses. Shoot Growth

Root Growth

Temperature in ºC

Minimum

Optimum

Maximum

Minimum

Optimum

Maximum

Warm season grasses

13

27 - 35

44 - 50

10 - 16

24 - 29

43

Cool season grasses

4

16 - 24

32

0

10 - 18

27

Grasses respond to cold temperatures by: ~ ~ ~ ~

leaf growth becoming spindly and less vigorous slowing root growth (producing new roots as well slowing the speed of growth) stopping growth completely (called entering dormancy), and the leaves may lose chlorophyll and turn brown.

In response to high temperatures: ~ ~ ~ ~

leaves may suffer heat stress and wilt, especially for cool season grasses. root growth then shoot growth (tillering) stops aging of the existing roots is greatly sped up, which weakens the whole root system the turf becomes disease prone.

Figure 44: : A fairway of a warm season grass, couch, becoming dormant and turning brown in winter. Photo: NZSTI

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Soil pH The term pH refers to a chemical scale of 0-14 that measures how acid or alkaline a substance is. Six and below are increasingly acidic, seven is a neutral substance, and eight and above are increasingly alkaline. All soils have a pH value that can be measured, and this can be shown on a soil test report. Soil pH affects the availability of some nutrients in the soil, and this can influence which species will grow well or poorly in a certain area.

Figure 45: The pH scale measures how acidic or alkaline a substance is. Every soil has a pH level, and this will influence which species of plants grow well there. Graphic: NZSTI When the soil is acidic (low pH) but nutrient availability is good, the fine fescues (Festuca spp.) and browntop (Agrostis capillaris) grow well. Although the fine fescues and browntop are generally considered as acid tolerant, both these species also perform well on neutral soils. However, on neutral soils these turf plants will often be out-competed by perennial ryegrass (Lolium perenne) that does not usually tolerate a soil pH below 5.0. See the diagram in Figure 38, where the preferred pH of different species is shown.

Mowing Mowing isn’t part of the natural environment, but it is a frequent and necessary feature of a sports turf environment. Turf plants are able to tolerate regular mowing by continuing to produce new leaves, making food via photosynthesis, and sending out tillers (extra stems) to widen growth by spreading. Leaf growth is still able to occur from the base of the plant (the crown), or any growing point as long as the growing point is located below the cutting height. However, mowing does change how the plant grows in several different ways. Turf plants adapt their growth to make the best of having their leaves cut off frequently, provided the cutting is consistent and not too severe.

Shoot density Generally, with a low mowing height and frequent mowing, shoot density increases. Close mowing helps shoot production (tillering) by encouraging the development of lateral buds, since growth is not put into tall stems and leaves. As a result, the turf area is covered with more shoots and leaves packed into the same space which results in a denser turf. Dense, healthy turf is usually a desirable result in the sports industry.

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Figure 46: Thin turf cover (left), contrasted with healthy, dense turf (right). Lower and more frequent mowing leads to an increase in turf density. Photos: NZSTI

Leaf texture As the mowing height is decreased and mowing frequency increased, leaf width is also reduced and leaf texture becomes finer, because the newer, young leaves are usually finer and adapted to the lower height than when left to grow to a higher height. The playing surface requirements of cricket pitches, bowling greens and golf greens need a uniform, smooth, dense, fine-textured, close-cut surface. The increased shoot density and finer leaf texture at these lower cutting heights results in improved surface smoothness, and in the case of a golf or bowling green improved green “speed”.

Figure 47: Low mowing heights and frequent mowing also encourage finer-textured turf growth: smaller and narrower leaves. The different in browntop leaf texture between the closely-mown greens and the higher-cut collar is very noticeable (left), while the example with Leptinella dioica (right), has happened naturally due to a small hollow on the right where the mower has had a slightly higher cutting height. Photos: NZSTI

Seedhead formation Regular mowing can break the normal seasonal development of cool season turfgrass species. In spring, one or more of the plant’s tillers begin a process of internode elongation (the growth of the section of stem between the nodes) to lift the seed-head above the rest of the leaves. In natural conditions, this extra height helps flowering, pollination and seed dispersal. Removal of the top of a grass plant by regular mowing stops flowering and seed production of the plant (with the exception of some plants including Poa annua, some Kentucky bluegrass (Poa pratensis) and ryegrass (Lolium spp.) cultivars). The plant’s only response to this is to keep producing new tillers. Cotula, starweed and the majority of warm season turfgrass species react differently to the mowing process; although mowing may remove many of the flowers, the reproduction process continues even at close mowing heights because many of the seed heads grow below the mowing height. BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Figure 48: Poa annua is one of the few cool season grasses which can produce seedheads below regular mowing height. Many other simply will not produce seeds because the higher-growing seedhead is removed by mowing, and instead put growth into tillering. Photo: NZSTI

Root development Generally, root growth is determined by the soil structure and soil moisture in the rootzone. Well-structured soil that is not compacted, and with the right amount of plant-available water, with support long and healthy roots. The main function of the turf plant’s leaves is to use the energy from the sun to produce food for the plant through photosynthesis. Therefore, removing leaf area by mowing can reduce carbohydrate production, and reduce root growth.

Figure 49: As mowing height is reduced, so is the rate and depth of root growth: Graphic: Staufenbeil, 2017

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5. Sports turf weeds As we said in the introduction to this course, a weed is simply a plant in the wrong place. As a sports turf area is often being managed in such a way to maintain a single type of plant, there’s a lot of potential for weeds to occur, from the obvious broadleaf species that stand out from a distance, to the less obvious other species of grasses that blend in and can increase in content unnoticed. Sports turf weeds are unwanted plants that are found in regularly mown turf. Regular mowing prevents many plants (ie trees, shrubs, vines) from growing in turf but are found in other land uses ie wasteland, agriculture, forestry or within a turf venue but not regularly mown ie secondary rough. As there is often confusion the following is a list of common turf weeds and those that are not. Table 12: Common turf weeds in alphabetical order Common broad leaf weeds ~ Annual mouse-ear

~ Liverwort

~ Twin cress

~ Allseed

~ Lotus

~ Turf speedwell

~ Bittercress

~ Moss- green

~ Wart cress

~ Broad leaved dock

~ Moss- Silver tip

~ White clover

~ Broad leaved fleabane

~ Mouse-ear chickweed

~ Wild carrot

~ Broad leaf plantain

~ Musky storksbill

~ Wireweed

~ Buttercup

~ Narrow leaved plantain

~ yarrow

~ Cape weed

~ Onehunga weed

Common grass weeds

~ Carrot weed - Oreomyrrhis

~ Oxtongue

~ Barnyard grass

~ Catsear

~ Parsley piert

~ Bristle grasses (Setaria spp)

~ Centella

~ Pearlwort

~ Browntop

~ Chickweed

~ Pennyroyal

~ Buffalo grass

~ Clustered dock

~ Pratia

~ Creeping bentgrass

~ Colobanthus

~ Purple cudweed

~ Couch (Cynodon dactylon)

~ Creeping buttercup

~ Purple loosestrife

~ Danthonia sp

~ Cotula dioca

~ Scirpus

~ Fine fescues

~ Cotula Maniototo

~ Scarlet pimpernel

~ Kentucky Bluegrass

~ Creeping cudweed

~ Scrambling speedwell

~ Kikuyu

~ Creeping oxalis

~ Selfheal

~ Mercergrass

~ Creeping sppedwell

~ Sedges- Nut grass

~ Narrow leaved carpetgrass

~ Creeping mallow

~ Umbrella sedge

~ Paspalum

~ Crowsfoot grass

~ Scotch Thistle

~ Poa annua

~ Cudweed

~ Sheeps sorrel

~ Prairie grass

~ Daisy

~ Silky cudweed

~ Ratstail

~ Dandelion

~ Small flowered buttercup

~ Ryegrass- perennial

~ Dichondra

~ Small flowered mallow

~ Ryegrass- Annual

~ Dock

~ Soldiers button

~ Summer grass

~ Doves foot

~ Spotted bur medic

~ Sweet vernal

~ Dwarf montia

~ Spurrey

~ Tall fescue

~ Fiddle dock

~ Starweed

~ Timothy

~ Field speedwell

~ Stinking mayweed

~ Yorkshire Fog BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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~ Frilled liverwort

~ Storksbill

~ Veld grass

~ Hairy buttercup

~ Subterranean clover

~ Witch grass

~ Hawkbit

~ Suckling clover

~ Hawkesbeard

~ Tillaea

~ Hydrocotyle

~ Toad rush

Weeds that are not considered turf weeds ~ Trees

~ Pine tree

~ Shrubs

~ Buddleia

~ Brushweeds

~ Broom, Gorse, Lupin

~ Pasture/cropping weeds

~ Nodding thistle, Ragwort, Fathen, Red clover

~ Wasteland weeds

~ Nightshade, fennel, Scentless chamomile

~ Garden weeds

~ Fumitory

Rather than provide comprehensive information in this study guide on such a long list of possible turf weeds, it’s more practical to look at existing New Zealand databases that can provide us with the identification of common turf weeds. There are two sources recommended for identifying broadleaf weeds: ~ The NZSTI Turf App, which you can download to your device for free. To identify common broadleaf turf weeds using this App by: • Picking a leaf from the weed and examining the features- ie leaf shape, hairiness, leaf style, number of leaflets and leaf margin. Note – use the Help button (top left) to describe and illustrate theses terms • Examine the weed for its growth habbit ie rosette, stolons, rhizomes, bunch • Use the Weeds Identifier APP to narrow down the potential broadleaved weeds until a good match is found. Tap the screen to select the most likely weed and find more images and information to confirm your identification ~ The Massey University Weeds Database, a publicaly-available website http://www.massey.ac.nz/ massey/learning/colleges/college-of-sciences/clinics-and-services/weeds-database/weeds-database_ home.cfm. To identify grass weeds, you can also use the the NZSTI Turf App: • • • •

•

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Picking a leaf from the weed and examining the features- ie leaf width, colour, tip shape, veins. Note-use the Help button (top left) to describe and illustrate theses terms Select a stem; peel back the leaves to expose the inner sheath at the base of the stem to view the colour Dig up a the grass plant and clean of the soil, exposing the roots. Examine the grass for its growth habit ie stolons and/or rhizomes or bunch growth habit Use the Weeds Identifier APP to narrow down the potential grass weeds until a good match is found. Tap the screen to select the most likely weed and find more images and information to confirm your identification Once you have identified the weed then find more about the weed from the other sources.

BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

Grass weeds Grass weeds can be hard to control in grass turf and are generally much more of a problem than broadleaf weeds. Most broadleaf weeds in grass turf are easily controlled using selective herbicides. This is because broadleaf weeds are different plants (dicotyledons) to grasses (monocotyledons). Many selective herbicides eliminate broadleaf weeds from grass turf without affecting the grass. Unfortunately, few grass killers remove grass weeds and leave the desired turfgrass unaffected. This is because most grasses (both grass weeds and turfgrasses) are very similar plants and if herbicide affects one grass, it will probably affect the desired species. There are exceptions: Haloxyfop (GallantⓇ and IgniteⓇ ) will remove all grasses except fine fescues, and triazine herbicides will not kill warm-season grasses. Turf managers must be able to identify one grass from another because identification of the weed is the very first step in working out a control strategy.

Broadleaf weeds The physical features of broadleaf weeds are often dependent on the growth life cycle of the plant, and the subsequent evolvement of survival mechanisms (eg rhizomes, tap roots, hairy leaves, prolific seeder etc). Weeds (including grass weeds) can be placed into three groups according to how long they live (their life cycle): ~ Annual weeds complete their life cycle in one year or less. ~ Biennial weeds have a two year life cycle. ~ Perennial weeds live for more than two years. Broadleaf weeds can be further categorised as per the following features: ~ Rosette or flat (e.g. dandelion, English daisy and Cape weed), with leaves that lie flat against the ground and radiate out from a central crown.

Figure 50: The rosette growth habit of hawkbit. Photo: NZSTI ~ Creeping or mat weeds, which creep along the ground and/or form a dense mat of interwoven stems close to the soil surface, e.g. Creeping oxalis, Hydrocotyle, yarrow, pearlwort and white clover. It can be difficult to group some weeds in this way. For example, daisy has a typical rosette form when it is young. However, as it grows it produces shoots from the crown, which develop into new rosettes. These in turn grow more shoots and rosettes, making a typical mat-like weed. There are other common terms used for identifying broadleaf weeds. You won’t need to know most of these words at this level, but they have been included because they are sometimes used in the NZSTI Turf App, and you may wish to look up their meanings here. BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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Table 13: Common terms and definitions for the identification of broadleaf weeds Term Stems Axial Internode Node Stolon Rhizome Leaves Simple Compound Trifoliate Pinnate Palmate Leaf margins (leaf edges) Crenate Serrate Entire Dissected Leaf arrangement Alternate Opposite Fascicles Whorled Inflorescence (flower head) Capitulum Panicle Raceme Spike Roots Fibrous roots Tap roots

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Definition Angle between petiole and stem Stem length between nodes Where the leaves meet the stem A horizontal stem above ground A horizontal stem below the ground Not divided or cut up Having several separate parts With three leaflets Leaflets in pairs along a midrib Leaflets all arising from one point Lobed With teeth Undivided Deeply cut One leaf per node In opposite pairs Clustered to one side Ringed around the node Daisy-type flower heads A branching head A group of flowers on a stalk A raceme without flower stalks A thin, highly branched root system which can grow horizontally and vertically in the soil A thick, dense root system which can penetrate the soil profile to great depths.

BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

Mosses, algae and liverworts Moss, algae and liverworts contain chlorophyll and are very simple plants. These plants are highly invasive and often outcompete desirable grasses for space in a range of conditions but especially in wet or shaded areas.

Mosses Mosses are primitive plants that are spread by spores, bulbils and leaf fragments. They quickly invade bare or thinly-covered turf areas. Mosses have no roots, seeds or veins in the leaf. Instead they have fine cellular threads (rhizoids) that serve as roots, and spores that carry out the function of seeds. There are many species of moss, but there are two main types that affect sports turf. They are: ~ Cushion or mat-types, e.g. both green moss amd silver tip moss (Bryum argenteum) ~ Surface creeping, e.g. some green moss (Eurphyncium spp.).

Figure 51: Cushion or mat-type form of green moss (left) and silver tipped moss (right). Photos: NZSTI Mosses are undesirable as they affect the appearance of the turf, and the roll and speed of the ball in sports like golf or the bowl in bowls. Moss is spread by its spores, and other plants parts such as bulbils or leaf fragments.

Figure 52: Filaments of green moss (left), bulbils (centre) and spore capsules (right). Photos: NZSTI Moss indicates a problem with the turf rather than being the cause. The problems must be addressed in order to manage the moss. Conditions that can favour moss include: ~ ~ ~ ~ ~ ~ ~

Excess surface moisture, e.g. over-watering Shady conditions Poor drainage or surface sealing Excessive thatch Dry patch Very low cutting height cut (silver tip moss) Thin turf cover BOTANY OF TURF PLANTS: STUDY GUIDE — VERSION 2.01

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~ ~ ~ ~

Late renovation or too little fertiliser after renovation Mower scalping or damage from wear. Poor fertility (low nitrogen, low pH