Warm Season Grass Weeds

May 11, 2018
  • Foxtail Warm Season

Warm Season Grass Weeds

In the previous blog, Types of Turfgrass Weeds, we told you that grasses have leaves with veins that turn parallel to each other and are two-ranked. We also classify these grass weeds by season; cool season and warm season. Here we share with you examples of warm season grass weeds and how to tell which weed you may have in your lawn.

 

Large Crabgrass (Digitaria sanguinalis)

Other Names: Hairy Crabgrass

Life Span: Warm season annual

CrabgrassDescription: Large crabgrass is light green and tillers profusely. The leaf blades are rolled in the bud, hairy on both sides, about ¼-inch wide, and taper to a point. The ligule is membranous and long, with toothed margins. Auricles are absent. The sheath is hairy and split. The root system is fibrous and dense. The seed head is divided into finger-like segments. The stem grows prostrate and sends down roots where the nodes come in contact with the soil. As a result of tillering, one plant may take up an area 6 inches in diameter. Large crabgrass germinates when soil temperatures reach 55° to 60°F. Large crabgrass establishment is favored by low mowing heights and light, frequent irrigation.

 

Goosegrass (Eleusine indica)

Other names: Silver Crabgrass

Life Span: Warm season annual

GoosegrassDescription: Goosegrass has dark green leaves with stems which become white toward the base. The leaf blades are folded in the bud, about ¼-inch wide, and taper to a point. The ligule is membranous, toothed, and divided at the mid-rib. Auricles are absent. The sheath is flattened, with a few long white hairs near the collar. The root system is shallow and fibrous. The seed head is divided into finger-like segments, but thicker and more robust than crabgrass. The stems are thick and grow prostrate with several basal tillers radiating from a common point. Goosegrass germinates later than crabgrass, requiring soil temperatures near 60° to 70°F. Goosegrass establishment is favored by compacted soil conditions and thin, open turfs.

 

Yellow Foxtail (Setaria glauca)

Other names: Pigeon grass

Life Span: Warm season annual

FoxtailDescription: Yellow foxtail is an erect, bunch-type grass. The leaf blades are rolled in the bud, keeled in the lower portions, with long cobwebby hairs on the upper surface near the base. The ligule is a fringe of short hairs. Auricles are absent. The sheath is smooth and flattened, and slightly bent at the nodes. The roots system is shallow and fibrous. The seed head is a single cylindrical, spike-like panicle. The stems grow erect. Yellow foxtail germination requires soil temperatures of 60° to 65° F. Yellow foxtail establishment is favored by thin open turfs.

 

Sandbur (Cenchrus pauciflorus)

Other names: None

Life Span: Warm season annual

SandburDescription: Sandbur is a low-growing grass that often forms mats. The leaf blades are folded in the bud, alternate, flat, narrow, tapered, and lack hairs. The ligule is a fringe of short hairs. Auricles are absent. The sheath is loose and flattened. The stem is smooth, branched, and flattened. The root system is fibrous. The seed head is a spike with 6 to 20 spiny burs which enclose the seed. Sandbur is a pale-yellow grass which prefers dry, sandy sites and low maintenance turf. The spiny burs can cause painful injuries.

 

Nimblewill (Muhlenbergia schreberi)

Other Names: None

Life Span: Warm season perennial

NimblewillDescription: Nimblewill is a thin, wiry, pale green grass. The leaf blades are rolled in the bud, short, narrow, pointed, and grow at a 45-degree angle from the stem. The ligule is membranous, jagged, and short. Auricles are absent. Long hairs are present at the collar. The stems are slender, smooth, and decumbent. The root system is shallow and fibrous. Nimblewill spreads by short stolons. The seed head is a loose spike-like panicle. Nimblewill forms circular patches as a result of its stoloniferous growth pattern. It is objectionable in cool season turfs because of its delayed greenup in the spring and early fall dormancy. It is usually found in shaded areas and drought-stressed turfs.

 

Reference

R.E. Gaussoin and A. R. Martin. (1997). Turfgrass Weed Identification and Prevention. In F. Baxendale, Ph.D., & R. Gaussoin, Ph.D., Integrated Turfgrass Management for the Northern Great Plains (pp. 84 – 96). Location: Nebraska

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