Scientific NameTridens flavus
A perennial with short, thick rhizomes that is most noticeable from August through October when these plants reach 4 or 5 feet in height and produce dark purple panicles
Leaves are somewhat flattened and appear folded in the sheath and have a relatively prominent white midvein. Leaves are 8 to 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. Sheaths are round and usually hairy only near the top.
Additionally, the short, thick rhizomes and purple seed head are characteristics that help in the identification of this weed.
Flower Seed Head
The seedhead is an open panicle that is dark purple in color. Individual spikelets are 6 to 8 mm long, 1 to 2 mm wide, and purple in color.
Seed length is 1.8 -2mm.
Purpletop is primarily a weed of hay fields, pastures, abandoned fields, and roadsides that is found from New Hampshire south to Florida. It prefers full sun, and moist dry conditions.
Leaf Hair on Upper Surface
hairs from base to tip
rolled in bud
Mature Leaf Width
less than 5 mm,
6 to 15 mm
less than 1 mm