What’s in Bloom | Purpletop Grass
August 10, 2020
Purpletop Grass (Tridens flavus) is a perennial, warm season grass native to central and eastern regions of the United States. It is adapted to shallow, infertile soils and can often grow along roadsides or in open woodlands.
Purpletop is a bunchgrass that typically grows between 2 to 6′ tall with narrow, glossy green leaves up to 2′ long. The dark purple seadhead is in an open cluster about 8 to 14″ long and covered with an oily substance (the reason for one of its nicknames, “grease grass”). The colorful seadheads appear in late summer and last through the fall. When planted en masse it gives a field a beautiful purple glow. It produces about 465,000 seeds per pound.
Purpletop grass is often eaten by livestock and the seedheads provide a food source for various species of birds and mammals. It also benefits biodiversity as a larval host to several butterfly, moth, and skipper species such as Common Wood Nymph (Cercyonis pegala), Crossline Skipper (Polites origenes), Little Glassywing (Pompeius verna), and Broad-winged Skipper (Poanes viator).