Plant Guide

Aristida purpurea Nutt. var. wrightii (Nash) Allred
Wright's threeawn

Kingdom Plantae -- Plants

Subkingdom Tracheobionta -- Vascular plants

Superdivision Spermatophyta -- Seed plants

Division Magnoliophyta -- Flowering plants

Class Liliopsida -- Monocotyledons

Subclass Commelinidae

Order Cyperales

Family Poaceae -- Grass family

Genus Aristida L. -- threeawn P

Species Aristida purpurea Nutt. -- purple threeawn P

Variety Aristida purpurea Nutt. var. wrightii (Nash) Allred -- Wright's threeawn P

Warning: This species may be mechanically injurious to livestock.

Alternate Names

Wright three-awn, wright threeawn, Aristida wrightii

Uses

Wright’s threeawn is grazed readily early in the spring. After seedheads form, it becomes less palatable. Cattle and horses graze it more readily than sheep and goats. If it greens up at the base late in the fall after other warm‑season grasses have matured, cattle and horses graze it again.

Status

Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status and wetland indicator values.

Description

Grass Family (Poaceae). Wright’s threeawn is a native, warm‑season, weak, short‑lived and perennial bunch grass. The height is between 10 and 20 inches. The leaf blade is rolled; threadlike; tufted, and twisting. The leaf sheath is mostly basal, rounded and open. The ligule is a row of short hair. The seedhead is a narrow panicle 6 to 8 inches long, purplish at first, turning straw yellow after maturity; the seeds are covered with stiff barbs.

Distribution: For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Management

This grass is never a key management species and most ranchers want to get rid of it. Close grazing in the spring will reduce it. Summer grazing deferments allow more vigorous warm-season grasses associated with it to dominate. Seed collects in the wool and mohair of sheep and goats that graze this grass during summer.

Establishment

Wright’s threeawn is one of the first warm‑season grasses to start growing in the spring. The seedheads appear within 30 days after growth starts. It becomes dormant in the summer and greens up again in the early fall. It reproduces mostly from seed and is a prolific seed producer. It grows best on calcareous to neutral sandy loam soils, but also grows on clay loams.

Cultivars, Improved and Selected Materials (and area of origin)

Please contact your local NRCS Field Office.

Reference

Leithead, H.L., L.L. Yarlett, & T.N. Shiflett. 1976. 100 native forage grasses in 11 southern states. USDA SCS Agriculture Handbook No. 389, Washington, DC.

Prepared By & Species Coordinator:

Percy Magee

USDA NRCS National Plant Data Center, Baton Rouge, Louisiana

Edited: 25june02 ahv; jul03 ahv; 21sep05 jsp; 070112 jsp

For more information about this and other plants, please contact your local NRCS field office or Conservation District, and visit the PLANTS Web site<https://plants.usda.gov> or the Plant Materials Program Web site <https://Plant-Materials.nrcs.usda.gov>

Attribution: U.S. Department of Agriculture