Identifying Grass Seedlings

Purpletop (Tridens flavus)

Perennial grasses


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.


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


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.