Giles, Floyd A.

Turgeon, Alfred J.

English

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y.oou./l-t6cno. 11 05cop. 5T"eft, mu«,afioniare camped below.=^^S=£li^ 'S LIBRARY ATLIMIVERSITY OFILLINOIS LIBRARYAT URBANA-CHAMPAIGNAGRICULTUREWKtRFORASSES OF ILLINOISmrwamm\'WXbf'-f?/li&P&ls:*mm4&University of Illinois at Urbana-Ghampaign/Gollege ofAgriculture/Cooperative Extension Service/Circular 1105The proper selection and care of turfgrasses in Illinois dependupon a knowledge of the environmental adaptation, cultural require-ments, and identification features of a number of grass species. Fre-quently, questions arise as to why a particular turf either failed toestablish or deteriorated under certain environmental conditions. Some-times the answer is that a poorly adapted turfgrass was planted or thatthe cultural requirements of a particular grass were not met. The firstprerequisite to determining the cause of turfgrass problems is an abilityto correctly identify different turfgrass species. The thinning and dis-coloration of rough bluegrass or red fescue on exposed sites in summer,the death of annual bluegrass under conditions of severe drouth and heatstress, the failure of Kentucky bluegrass to persist in the shade, and thetan color of zoysiagrass in spring are all situations requiring an accurateidentification of the particular grass present in order to determine thecause of the "diseased" condition of the turf.This circular is intended as a guide to learning the important vegeta-tive features for identifying various turfgrass species found in Illinois.Refer to circular 1082, "Illinois Lawn Care and Establishment," circular1076, "Turfgrass Pest Control," and other extension publications formore specific information on the culture of turfgrasses.TURFGRASS MORPHOLOGYThe mature turfgrass plant is made up of fibrous roots and of shootscomposed of elongated and unelongated stems with long, narrow leavesarising from the stem nodes and terminals. Growth habits (Fig. 1) in-clude bunch-type, rhizomatous, and stoloniferous. The bunch-typegrowth habit is generally found in annual bluegrass, colonial bentgrass,Chewings fescue, tall fescue, and the ryegrasses. Lateral development ofgrass plants is by tillering, a process by which new shoots arise fromvegetative buds in the axils of the leaf sheaths of older shoots. As theenclosing leaf sheath decays, the newly developed shoot (tiller) is re-vealed. Bunch-type turfgrasses generally have poor recuperative abilityafter injury; reseed bare spots in these turfs to enhance recovery.Grasses with a rhizomatous growth habit include Kentucky bluegrass,Canada bluegrass, and creeping red fescue. In addition to tillering, thesegrasses can spread laterally with the growth of below-ground stemscalled rhizomes. These develop from the same vegetative buds as dotillers, but the new rhizome breaks through the enclosing leaf sheath andPrepared by A. J. Turgeon, Extension Turfgrass Specialist, and F. A.Giles, Extension Specialist in Home Landscape.Figure 1. Turfgrass growth habits: (a) bunch-type (insert shows tillering),(b) rhizomatous, and (c) stoloniferous.grows laterally through the soil. This type of growth habit facilitatesrapid growth into bare areas that have resulted from diseases, insects,traffic, and other factors.A stoloniferous growth habit results from the development of stolons.Like rhizomes, stolons are horizontally growing stems that break throughan enclosing leaf sheath, but their lateral growth is along the surface ofthe ground. Stoloniferous grasses include rough bluegrass and creepingbentgrass. When seeded with other grasses, stoloniferous grasses tend tobecome isolated into distinct patches that disrupt the uniformity of theturf; hence, they are best used in pure stands for specific types of usesand environmental conditions.Grasses that have both stolons and rhizomes include the two warm-season species, bermudagrass and zoysiagrass. As with the strictly stolon-iferous grasses, these are best used in pure stands.LEAF STRUCTURESThe turfgrass leaf is composed of an upper flattened portion calledthe blade and a lower tubular portion called the sheath. At the junctionof the leaf blade and sheath are the ligule, the collar, and, in some species,auricles. These are the three principal structural features used in iden-tifying different turfgrass species.The ligule (Fig. 2) is a tongue-like outgrowth that may be a fringeof hairs, as in bermudagrass and zoysiagrass, or a membranous structureFigure 2. Ligule structures: (a) fringe of hairs, (b) smooth membrane, and(c) jagged membrane.Figure 3. Continuouscollar (left) and di-vided collar (right).of a particular size and shape. Kentucky bluegrass has a very short, flat,membranous ligule, while creeping bentgrass has a long, pointed, mem-branous ligule. A membranous ligule may be smooth across the top, asin redtop, or jagged, as in colonial bentgrass.The collar (Fig. 3) is a light green band at the base of the leafblade; it varies in size and shape according to species. Kentucky blue-grass has a narrow, continuous collar, while tall fescue has a broad,divided collar.The auricles (Fig. 4) are appendages projecting from each side ofthe collar. They may be long and slender, as in annual ryegrass, shortand blunt, as in tall fescue, or absent, as in Kentucky bluegrass.Figure 4. Turfgrass leaves with (a) long and slender auricles, (b) short andblunt auricles, and (c) no auricles.Figure 5. Folded (left)and rolled (right) ver-nation.An additional feature helpful in identifying turfgrass species is thevernation (Fig. 5), the arrangement of leaves enclosed within the olderleaf sheaths. This characteristic is easily demonstrated with the rye-grasses. Perennial ryegrass has a folded vernation, with leaf marginsmeeting but not overlapping, while annual ryegrass has a rolled vernation,with leaf margins overlapping.The leaf blades differ considerably among turfgrasses. The blue-grasses have smooth leaf blades (Fig. 6a), while ryegrasses, fescues, andbentgrasses have prominent veins on the upper leaf surface (Fig. 6b).Under moisture stress, the leaf blades of Kentucky bluegrass (Fig.6c) and red fescue (Fig. 6d) may fold in response to changes in turgorpressure of the bulliform cells (large, thin-walled epidermal cells lo-cated on the upper leaf surface). The two translucent lines observedFigure 6. Smooth leaf blades of bluegrass (a); ryegrass leaf blades withprominent veins (b); response of leaf blades to moisture stress in Kentuckybluegrass (c) and red fescue (d).Figure 7. "Boat-shaped"leaf tip of bluegrass.when a Kentucky bluegrass leaf blade is held up to the light are dueto the parallel groups of bulliform cells located on either side of themidrib.The shape of the leaf tip is an important feature for distinguishingthe bluegrasses from other turfgrass species. Bluegrasses have a char-acteristic "boat-shaped" leaf tip (Fig. 7), while the leaf tips of mostother turfgrasses are flat and pointed. The shape of the leaf blade mov-ing toward the tip also helps distinguish Kentucky bluegrass and annualbluegrass, which are parallel sided, from Canada bluegrass and roughbluegrass, which taper toward the leaf tip.BLUEGRASSES (Poasp.)Bluegrasses include several species that are important as turfgrasses.These species differ substantially in general appearance, growth habit,environmental adaptation, and cultural requirements; however, they allhave certain structural features in common:• folded vernation (young leaf blades are folded as they emerge fromthe enclosing sheaths of older leaves)• boat-shaped leaf tip (the leaf blade gathers toward the tip to forma three-dimensional shape like the prow of a boat)• smooth leaf blades with parallel translucent lines on either side ofthe central midrib• absence of auricles• membranous ligulesKentucky bluegrass (Poa pratensis L.)Kentucky bluegrass is the principal turfgrass used in Illinois. It isadapted to a wide range of environmental conditions and provides anattractive turf when maintained under proper cultural conditions. Itperforms best in open, sunny areas under moderate to high fertilization,moderate mowing heights (lJ/2" to 2"), and supplemental irrigationduring drouth periods.Structural features of Kentucky bluegrass• very short, flat, membranous ligule• parallel-sided leaf blades• rhizomatous growth habit• medium-coarse to medium-fine leaf texture, de-pending upon cultivar and cultural intensity• light to dark green color, depending upon cul-tivar, time of year, and cultural intensityAnnual bluegrass (Poa annua L.)When maintained under moderately close mowing and frequent ir-rigation, annual bluegrass forms a very dense, fine-textured, and vig-orous turf during the cooler months of the growing season. It survivesreasonably well on compacted soils and is well adapted to moist, shadedconditions. However, its poor tolerance of heat and drouth stress duringthe summer make it an undesirable weed throughout most of Illinois.Although rarely planted intentionally, it is frequently the major com-ponent of such intensively cultured turfs as golf course greens, tees, andfairways.Structural features of annual bluegrass• long, pointed, membranous ligule• parallel-sided to slightly tapering leafblades• bunch-type to weakly stoloniferous growthhabit• light green colorCanada bluegrass (Poa compressa L.)Canada bluegrass forms an open turf of low density and generallypoor quality. It is adapted to cool climates and acid, drouthy soils oflow fertility. It grows best when clipped at 3 to 4 inches.Structural features of Canada bluegrass• flat, membranous ligule of medium length• short, tapering leaf blades• rhizomatous growth habit• dull, bluish-green leaves of medium texture• reddish coloration of leaf margins in earlyspringRough blugrass (Poa trivialis L.)Rough bluegrass forms a dense, semi-prostrate turf that is adaptedto cool, moist, shaded environments. It frequently invades other turfsthat are growing on poorly drained, fertile soils during the cooler monthsof the growing season. During the summer months, however, roughbluegrass is usually thinned and discolored because of its poor heat,drouth, and disease tolerance. As it is not compatible with other turf-grasses, its use is usually limited to wet, shaded areas where otherturfgrass species do not persist.Structural features of rough bluegrass• long, membranous, slightly toothed ligule• tapering leaf blades that appear shiny on theundersides• stoloniferous growth habit• roughened, "onion-skin" appearance on lowerportion of mature leaf sheath• light green to yellowish-green color10BENTGRASSES (Agrostis sp.)The bentgrasses include four species that are important as turf-grasses in Illinois. Although very limited in their general adaptation anduse, bentgrasses provide the dense, closely clipped turfs important forsuch popular sports as golf. Bentgrasses have these structural featuresin common:• rolled vernation• membranous ligules• flat, tapering leaf blades with pointed tips• prominent veins on the upper sides of leaf blades• absence of auriclesCreeping bentgrass (Agrostis palustris Huds.)Creeping bentgrass forms a smooth, dense turf that, when main-tained properly, is suitable for use in golf course putting greens andtees, bowling greens, grass tennis courts, and exotic lawns. Its culturalrequirements include close (*4" or less), frequent mowing; regularapplications of fungicides for disease control ; frequent irrigation ; andsome cultivation or topdressing. It is not compatible with other turf-grasses and is frequently found as a serious weed in Kentucky bluegrasslawns.Structural features of creeping bentgrass• long, rounded, membranous ligule• medium-fine leaf texture (2 to 3 mm wide)• stoloniferous growth habitColonial bentgrass (Agrostis tenuis Sibth.)Colonial bentgrass is not as well adapted to Illinois as to the milderclimates of New England and the Pacific Northwest; however, it issometimes found in fairway turfs of northern Illinois golf courses. It11does best at slightly higher (1/2" to %") mowing heights than forcreeping bentgrass; otherwise, their cultural requirements are similar.Once considered an important component of lawn seed mixtures, the useof colonial bentgrass is now discouraged because of its tendency to be-come the dominant species in a turf.'! i " i i !'. !i!| N! 1 i nil1 j ; 1IStructural features of colonial bentgrass• medium-long, flat, notched, membranous ligule• medium-fine leaf texture (1 to 3 mm wide)• bunch-type growth habit, but sometimes with shortstolons or rhizomesVelvet bentgrass (Agrostis canina L.)Velvet bentgrass forms a very fine-textured, extremely dense turfwhen maintained under close mowing and meticulous care. Its highthatching tendency and slow shoot growth limit it primarily to the NewEngland States, where it is especially well adapted. Velvet bentgrass isoccasionally observed as small, tight patches in some shaded puttinggreens on Illinois golf courses.Structural features of velvet bentgrass• long, pointed, membranous ligule• very fine leaf texture (less than 1 mm wide)• stoloniferous growth habit12Redtop (Agrostis alba L.)Redtop forms an open, coarse-textured turf that is adapted to cool,moist (or wet) environments. When planted as a component of seedmixtures, it may persist as unsightly, weedy tufts in the lawn. It isintolerant of temperature extremes, shade, traffic, or close mowing. Red-top is used primarily for low-quality turfs for soil stabilization on road-sides, ditches, and waterways.Structural features of redtop• very long, rounded, membranous ligule• medium-coarse leaf texture (3 to 5 mm wide)• rhizomatous growth habit• dull, gray-green colorRYEGRASSES (Lolium sp.)Ryegrasses have been used traditionally as nurse grasses in lawnseed mixtures or for the establishment of temporary lawns. Their quickgermination and vigorous seedling growth make them suitable for usewhere rapid establishment and soil stabilization are desired. Because oftheir intolerance of temperature extremes, drouth, and certain diseases,ryegrasses sometimes behave like annuals or short-lived perennials. Rye-grasses have the following structural features in common:• membranous ligules• presences of auricles• flat, tapering leaf blades with prominent veins on the upper sides,smooth and glossy on the lower side• bunch-type growth habitPerennial ryegrass (Lolium perenne L.)Perennial ryegrass is adapted to cool, moist conditions and may per-sist during the winter and summer seasons, provided severe temperaturesdo not occur. Because of its rapid germination and vigorous seedlinggrowth, it is frequently used in seed mixtures as a nurse grass for quick13cover. A fairly wear-tolerant grass, perennial ryegrass is sometimes usedfor overseeding athletic field turfs that have been injured from play. Themowing quality of perennial ryegrasses has generally been poor becauseof the tough vascular bundles in the leaves; improved varieties, however,such as Manhattan, Pennfine, and NK-200 have better mowing qualityand provide turfs that are finer-textured, denser, and darker green thancommon perennial ryegrass.Structural features of perennial ryegrass• folded vernation• pointed, membranous ligule• short, non-clasping auriclesAnnual ryegrass {Lolium multiflorum Lam.)Annual ryegrass is similar to perennial ryegrass but is less tolerantof cold, heat, and drouth stresses and typically behaves like an annual orshort-lived perennial. Its use as a nurse grass is discouraged because ofits objectionably coarse texture and its severe competition with moredesirable turfgrasses during establishment. It is occasionally recom-mended as a temporary lawn grass for soil stabilization until there is amore favorable season to establish Kentucky bluegrass.Structural features of annual ryegrass• rolled vernation• short, flat, membranous ligule• long, slender, clasping auricles14FESCUES (Festuca sp.)The fescues make up a highly variable genus that includes bothcoarse- and fine-textured species. These species differ substantially ingrowth habit, environmental adaptation, cultural requirements, and use.As a group the fescues are adapted to drouthy, infertile soils and possessgenerally good wear tolerance. Fescues have the following structuralfeatures in common:• short, flat, membranous ligule• prominent veins on upper side of leaf bladeRed fescue (Festuca rubra L.)Red fescue forms a very fine-textured, dense, medium to dark-greenturf. It is best adapted to cool, dry, shaded environments and a low tomoderate intensity of culture. It is relatively intolerant of high tempera-tures, poorly drained soils, and saline soils. It is frequently used as acompanion grass in mixtures with Kentucky bluegrass for moderatelyshaded sites. There are two subspecies of red fescue that differ princi-pally in growth habit: creeping red fescue (subspecies rubra) is arhizomatous grass, while Chewings fescue (subspecies commutatd) is abunch grass that spreads by tillering only.Structural features of red fescue• folded vernation• very narrow leaves, folded or flat depending uponmoisture conditionsTall fescue (Festuca arundinacea Schreb.)Tall fescue is a very coarse-textured grass that is adapted to a widerange of environmental conditions. It has good heat, drouth, and weartolerance, and it persists fairly well in moderately shaded environments.It provides a satisfactory turf on sites that receive a low intensity of15culture; however, it responds well to increased fertilization and irriga-tion if it is mowed at a height of at least U/2 inches. Because tall fescueis not compatible with other turfgrasses, it should be planted alone athigh seeding rates (6 to 8 pounds per 1,000 square feet) to ensure thebest quality turf., Jt'! - 1 ' !.((| \\ \\M f i\ 1 h M! i 1 Ml H M !l[j!'! [;; f'''•']1 ;[ i\\\l : 1 \\ \ f \trV *»Structural features of tall fescue• rolled vernation• wide, stiff leaf blades with prominent veins onthe upper side• bunch-type growth habit, but sometimes withshort rhizomes• short, stubby auriclesBERMUDAGRASS (Cynodon dactylon (L.) Pers.)Bermudagrass is a warm-season species used occasionally as a turf-grass in southern Illinois. It is also found as weedy patches in bluegrassand bentgrass turfs. It forms a dark-green, dense, vigorous turf ofmedium-fine texture. Its heat and drouth tolerance are excellent, butpoor cold tolerance and winter discoloration severely limit the practicaluse of bermudagrass in Illinois.Structural features of bermudagrass• folded vernation• ligule is a fringe of hairs• long hairs extending from the collar• smooth leaf blade with short hairs• both stolons and rhizomes present16ZOYSIAGRASS (Zoysia japonica Steud.)Zoysiagrass is a warm-season turfgrass frequently seen in lawns andon golf course fairways in southern Illinois. It forms a dense, tough,slow-growing turf and has good heat, drouth, and cold tolerances. Its tanappearance while dormant during the cool months of the year (Octoberto May) may be objectionable, but green dyes may be used to provideartificial color. The invasion by cool-season grasses and broadleaf weedsduring winter should be controlled with herbicides in order to maintaina uniform turf. Zoysiagrass is propagated by plugs or shredded sod andis very slow to establish, usually requiring two to three years.Structural features of zoysiagrass• rolled vernation• ligule is a fringe of hairs• long hairs extending from the collar• smooth leaf blade with long, slender hairsextending from the upper side• both stolons and rhizomes presentThe Illinois Cooperative Extension Service provides equal opportunities in programs andemployment.Urbana, Illinois January, 1975Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June30, 1914, in cooperation with the U.S. Department of Agriculture, JOHN B.CLAAR, Director, Cooperative Extension Service, University of Illinois atUrbana-Champaign.8M—1-75—29718r

Turfgrasses of Illinois / prepared by A.J. Turgeon and F.A. Giles 1105

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