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Weed Identification

eastern gamagrass



Scientific Name

Tripsacum dactyloides

Synonyms (former Scientific Names):

Coix dactyloides


Eastern gamagrass is a perennial warm-season bunch type grass with large, thick rhizomes that may reach up to 6 ft in height.


Leaf blades may reach 2 feet in length and 1 inch in width, and are rough to the touch but mostly without hairs except those that occur at the base of the upper leaf surfaces. Leaves lack auricles but have a ligule that is a fringe of hairs, approximately 1 to 1 1/2 mm in length. Ligules may be fused at the base taking on the appearance of a ligule that is both membranous and a fringe of hairs. The sheath is without hairs and is split at least part way up the stem with overlapping margins.

Identifying Characteristics

The large, thick rootstocks and relatively large leaves of this plant helps to distinguish it from almost any other grass. Additionally, the rather unique terminal seedhead is a good identifying characteristic of this species. Plants have very thick rootstocks, usually much larger than the width of the plant itself.

Flower Seed Head

Eastern Gamagrass has a conspicuous spike seed head that is 'jointed'. Seedheads (usually 1 to 3) are terminal spikes that are from 4 to 12 inches in length. Spikes consist of many tightly fused spikelets that eventually take on the appearance of being 'jointed'.

Where Found

It is native to most of the eastern part of the U.S. This grass is found from Massachusetts south to Florida. It is primarily a weed of pastures, hay fields, abandoned fields, roadsides, and along the edges of woods. It is most often grown for a forage crop. It does best in well drained soils.

Leaf Hair on Upper Surface

hairs on basal half only

Leaf Arrangement

rolled in bud

Mature Leaf Width

more than 15 mm





Life Cycle



not present



Ligule Length

1-2 mm

Plant Type