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The Cool-season Turfgrasses: Identification

Turfgrass Identification

To develop successful lawn management programs and avoid problems, you must be able to identify turfgrass

species. Species react differently to management practices such as mowing, fertilization, and liming; thus, you

should know which grasses are present in the lawn so that you can adjust your management program accordingly.

Also, there are several pesticides that are safe to apply to some turfgrass species, but not others. If you apply a

herbicide that is safe only on Kentucky bluegrass to a fine fescue lawn, serious damage could result and you may

have to replace the lawn. Before making important lawn management decisions, make sure that you can identify the

turfgrass species present at the site.

Identification of the cool-season turfgrass species is not difficult once you learn how to recognize a few plant

structures and some subtle features associated with those structures. Descriptions of the plant parts used in

identification of turfgrasses are provided in the following paragraphs. Some of these have been discussed in “The

Cool Season Turfgrasses: Basic Structures, Growth and Development”. Diagrams and descriptions of identifying

features of cool-season turfgrass species are provided in this section.

Vernation

Vernation is a term used to describe how the youngest grass leaves are arranged in the shoot (inside of the leaf

sheath between the collar region and the crown). Grasses with folded vernation have leaves that are folded in the

shoot and appear V-shaped in shoots that are cut in half across the width (cross-sectioned). Leaves with rolled

vernation are circular or “rolled" in the shoot and do not have folds (Fig. 1). To determine if a grass specimen has

folded or rolled vernation, hold the shoot between your thumb and index finger and roll it. If it rolls like a straw, it

has rolled vernation, if it lies flat and has edges, it is folded. You can also determine vernation by cutting a cross-

section of the shoot just below the collar region and looking at the leaf arrangement.

Figure 1. Examples of folded and rolled vernation

CENTER FOR TURFGRASS SCIENCE

Page 1 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science

Leaf Blades

Leaf blades have certain characteristics that are useful in turfgrass identification. Some species have leaf blades with

a single prominent vein running lengthwise down the center of the blade. Others have many equal-sized veins (no

dominant mid-vein) running lengthwise over the entire width of the leaf blade (Fig. 2). A few species have both a

prominent mid-vein and many smaller veins oriented lengthwise over the entire width of the blade. Certain turfgrass

species have a glossy appearance on the underside of the leaf blade, whereas others are dull (not glossy). Some

turfgrasses have leaf blades that terminate in a flat point, whereas others have leaf blade tips that are keeled

(sometimes referred to as a ‘boat-shaped’ tip) (Fig. 2).

Figure 2. Leaf blade with prominent vein running lengthwise in center of blade (a) and one with many equal-sized

veins (no dominant mid-vein) running lenghtwise over the entire width of the blade (b). Diagram of turfgrass leaf

tips showing keeled, and flat and pointed.

Ligules and Auricles

Ligules are membranous or hairy tissues located at the junction of the leaf blade and leaf sheath. Depending on the

species, ligules can be membranous, a fringe of hairs, or absent (Fig. 3A). None of the cool-season turfgrasses have

ligules that appear as a fringe of hairs, but this feature is common on many weed grasses and most warm-season

turfgrasses. Auricles are slender extensions of the collar and are located at the junction of the leaf blade and leaf

sheath. They can be long and clasp around the stem or shoot, small or rudimentary, or absent (Fig. 3B).

Figure 3. In turfgrasses, ligules may be membranous, hairy, or entirely abscent. (B) Auricles may be long and

clasping, small or rudimentary, or abscent.

Page 2 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science

Growth Habit

Growth habits of cool-season turfgrasses are either rhizomatous (producing rhizomes), stoloniferous (producing

stolons), or bunch type (a species that does not produce rhizomes or stolons — only tillers). In some cases, the

growth habit of turfgrasses can be useful in identification. For example, one way to distinguish Kentucky bluegrass

from rough bluegrass is that rough bluegrass produces stolons and Kentucky bluegrass produces rhizomes.

Figure 4. Rhizomatous, bunch, and stoloniferous growth habits.

The Seed Head

Although seed head characteristics are among the best identifying features of turfgrass species, they are often

removed by mowing. Where seed heads can be observed, they are classified as panicle types, spike types, or

recemes. Recognizing difference among these seed head types can be useful in distinguishing among the cool-season

turfgrass species.

The Cool-season Turfgrasses: Identification — Center for Turfgrass Science Page 3 of 9

Figure 5. Three types of turfgrass seed head; panicle, spike and raceme.

Identifying Features of Cool-Season Turfgrass Species

Kentucky bluegrass

• Folded vernation

• Prominent mid-vein (no other veins noticeable), leaf blade dull underneath, keeled leaf tip

• Auricles absent

• Short, membranous ligule

• Rhizomatous growth habit

• Panicle-type seed head

Page 4 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science

Kentucky Bluegrass

Rough bluegrass

• Folded vernation

• Prominent mid-vein (no other veins noticeable), leaf blade glossy underneath, keeled leaf tip

• Auricles absent

• Short, membranous ligule

• Stoloniferous growth habit

• Panicle-type seed head

Rough Bluegrass

Perennial ryegrass

• Folded vernation

• Prominent mid-vein with many smaller veins oriented lengthwise over the entire width of leaf blade,

leaf blade glossy underneath, keeled leaf tip

• Small, rudimentary auricles

• Short, membranous ligule

• Bunch-type growth habit

• Spike-type seed head

Page 5 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science

Perennial Ryegrass

Annual ryegrass

• Rolled vernation

• Prominent mid-vein with many smaller veins oriented lengthwise over the entire width of leaf blade,

leaf blade glossy underneath, keeled leaf tip

• Long, clasping auricles

• Short, membranous ligule

• Bunch-type growth habit

• Spike-type seed head

Annual Ryegrass

Page 6 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science

Fine fescues

• Folded vernation

• Very narrow, folded leaf blades — in most cases veins not visible, leaf blade dull underneath, keeled

leaf tip

• Auricles absent

• Short, membranous ligule

• Bunch-type or rhizomatous growth habit

• Panicle-type seed head

Fine Fescues

Tall fescue

• Rolled vernation

• Blades have many equal-sized veins (no dominant mid vein) running lengthwise over the entire width

of the leaf blade, leaf blade dull underneath, pointed leaf tip

• Auricles absent

• Short, membranous ligule

• Primarily bunch-type growth habit, sometimes short rhizomes are present

• Panicle-type seed head

Page 7 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science

Tall Fescue

Creeping bentgrass

• Rolled vernation

• Blades have many equal-sized veins (no dominant mid vein) running lengthwise over the entire width

of the leaf blade, leaf blade dull underneath, pointed leaf tip.

• Auricles absent

• Tall, membranous ligule

• Stoloniferous growth habit

• Panicle-type seed head

Creeping Bentgrass

Prepared by Peter Landschoot, professor of turfgrass science

Page 8 of 9The Cool-season Turfgrasses: Identification — Center for Turfgrass Science