Department of Crop and Soil Sciences - Cooperative Extension

Prepared by Peter Landschoot, professor of turfgrass science

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

examples of rolled and folded vernation

Fig. 1. Examples of folded and rolled 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&&8221; 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.

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).

diagram showing a leaf blade with a prominate center vein and one with many equal-sized veins and a diagram of leaf tips, keeled and flat, pointed

Fig. 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).

examples of ligules and auricles

Fig. 3 (A). In turfgrasses, ligules may be membranous, hairy, or entirely abscent. (B) Auricles may be long and clasping, small or rudimentary, or abscent.

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.

Rhizomatous, bunch, and stoloniferous growth habits.

Fig. 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.

labeled diagram of the three types of turfgrass seed heads

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

Identifying Features of Cool-Season Turfgrass Species

Kentucky bluegrass

sketch of Kentucky bluegrass auricle and seed head

Kentucky bluegrass

Rough bluegrass

sketch of rough bluegrass auricle and seed head

Rough bluegrass.

Perennial ryegrass

sketch of perennial ryegrass auricle and seed head

Perennial ryegrass.

Annual ryegrass

sketch of annual ryegrass auricle and seed head

Annual ryegrass.

Fine fescues

sketch of fine fescue auricle and seed head

Fine fescues

Tall fescue

sketch of tall fescue auricle and seed head

Tall fescue

Creeping bentgrass

sketch of creeping bentgrass auricle and seed head

Creeping bentgrass