University of Missouri Extension

IPM1024, Revised October 2010

Identifying Grass Seedlings

Purpletop (Tridens flavus)

Perennial grasses

Description

Purpletop is a perennial with short, thick rhizomes and is most noticeable from August through October when the plant reaches 4 or 5 feet in height and produces dark purple panicles. The leaves are somewhat flattened and appear folded in the sheath and have a relatively prominent white midvein. Leaves are 8–17 mm wide, usually hairy except near the bases, lacking auricles, and with a ligule that is a fringe of hairs less than 1 mm in length.

Purple paniclesPurple panicles.
 

Collar region SeedlingsCollar region: short, hairy ligule.
Right, purpletop seedlings.
 

Habitat

Primarily a weed of hay fields, pastures, abandoned fields and roadsides.

Distribution

Purpletop is found throughout the eastern half of the United States and can be found throughout Missouri.

Similar species

Barnyardgrass or johnsongrass may occur in similar environments and have a similar appearance as seedlings, but purpletop could easily be distinguished from these other species by its small hairy ligule.

IPM1024, revised October 2010

IPM1024 Identifying Grass Seedlings | University of Missouri Extension

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