Grass Indentification

Identifying grasses can be a challenging task due to the numerous species and subtle differences between them. However, by examining specific characteristics of the grass, such as leaf shape, growth habit, and inflorescences, you can narrow down the possibilities and identify the grass species. Here are some key features to observe when trying to identify grasses:

Grass anatomy, above ground
  1. Leaf blade: Observe the shape, width, and texture of the leaf blade. Some grasses have fine, needle-like leaves, while others have broader leaves. The leaf blade's edges may be smooth, serrated, or have tiny hairs. Additionally, note the color and any distinct patterns, such as stripes or a change in color along the midrib.
  2. Leaf sheath and ligule: The leaf sheath is the part of the leaf that wraps around the stem, while the ligule is a small projection at the junction of the leaf blade and sheath. The presence, shape, and size of the ligule can be an important identifying feature.
  3. Growth habit: Observe how the grass grows, whether it forms clumps (bunch-type) or spreads through stolons or rhizomes (creeping-type). The growth habit can help narrow down the species or group of grasses.
  4. Vernation: This refers to how the grass leaf is folded or rolled in the bud. Some grasses have leaves that are folded, while others have leaves rolled in the bud. This characteristic can be helpful in distinguishing between different species.
  5. Inflorescence: The inflorescence is the flowering part of the grass. Note the shape, size, and arrangement of the flower spikelets. Grass inflorescences can be spike-like, panicle-like, or raceme-like, with various branching patterns.
  6. Seed head: Examine the seed head's shape, size, and color, as well as the arrangement and appearance of the seeds or spikelets.
  7. Stems: Observe the shape, size, and color of the grass stems. Some grasses have round stems, while others have flattened or triangular stems. The stem joints or nodes may also be swollen or constricted, which can be a useful identifying feature.
  8. Root system: Although not always practical, examining the root system can provide additional clues. Some grasses have fibrous root systems, while others have rhizomes or stolons.
  9. Habitat and region: Consider the grass's habitat, as certain species are more likely to be found in specific environments, such as wetlands, forests, or prairies. Additionally, note the region and climate where the grass is growing, as some grasses are native to particular areas or thrive in specific climates.

To identify grasses, it is helpful to consult a field guide or online resources that provide images and descriptions of grass species in your region. By comparing the observed characteristics with the information in these resources, you can often determine the grass species or at least narrow it down to a small group of possibilities.

Identifying characteristics of the most common lawn grasses

Kentucky Bluegrass

Kentucky bluegrass (Poa pratensis)

  • Leaf blade: Narrow, with a boat-shaped tip, and a prominent midrib on the upper side. The leaf edges may have a slightly rough texture.
  • Growth habit: Spreads through rhizomes, creating a dense, interconnected turf.
  • Vernation: Folded.
  • Inflorescence: Pyramid-shaped panicle with branches that spread outward, containing small spikelets on delicate stalks.
  • Color: Deep green to bluish-green.
Bermuda grass

Bermudagrass (Cynodon dactylon)

  • Leaf blade: Narrow, flat, and slightly rough on the upper side, with a pointed tip.
  • Growth habit: Spreads vigorously through both stolons and rhizomes.
  • Vernation: Folded.
  • Inflorescence: A finger-like arrangement of spikes radiating from a central point, with each spike containing several spikelets.
  • Color: Medium to dark green.
Zoysia grass

Zoysiagrass (Zoysia spp.)

  • Leaf blade: Narrow, stiff, and sharp, with a fine texture and a tapering tip. The upper side of the leaf blade is often hairy near the base.
  • Growth habit: Spreads through both stolons and rhizomes, creating a dense turf.
  • Vernation: Rolled.
  • Inflorescence: A slender, branched panicle containing small spikelets.
  • Color: Medium to dark green.
St. Augustine grass

St. Augustine grass (Stenotaphrum secundatum)

  • Leaf blade: Broad, flat, and relatively coarse, with a rounded or tapering tip. The leaf edges may have a slightly rough texture.
  • Growth habit: Spreads primarily through stolons, forming a dense, carpet-like lawn.
  • Vernation: Folded.
  • Inflorescence: A spike-like raceme containing several spikelets, often with a purplish hue.
  • Color: Medium to dark green.
Fescue grass

Fescue grass (Festuca spp.) - includes fine fescue and tall fescue

  • Leaf blade: Fine fescue has very narrow, needle-like leaves, while tall fescue has broader leaves with a prominent midrib. Both have a slightly rough texture on the upper side.
  • Growth habit: Bunch-type growth, forming clumps.
  • Vernation: Rolled (fine fescue) or folded (tall fescue).
  • Inflorescence: Fine fescue has a panicle-like inflorescence, while tall fescue has a more spike-like inflorescence. Both contain small spikelets.
  • Color: Medium to dark green.
Rye grass

Perennial ryegrass (Lolium perenne)

  • Leaf blade: Narrow, with a shiny appearance on the upper side and a tapering tip. The leaf edges have a slightly rough texture.
  • Growth habit: Bunch-type growth, forming clumps.
  • Vernation: Folded.
  • Inflorescence: A spike-like inflorescence containing spikelets that are arranged alternately on a central stem.
  • Color: Bright green to dark green.

By observing these identifying characteristics, you can distinguish between the most common lawn grasses and better understand their growth habits and appearance. Keep in mind that variations can occur within each species, and hybrid cultivars may exhibit unique features.