Bromus tectorum L.


Bromus tectorum is an erect-stemmed annual grass that grows to about 8-25 in. (20-70 cm) in height.
The leaf sheaths and blades are covered with soft short hairs. The leaves are 0.08-0.16 in. (2-4 mm) wide and up to 8 in. (20 cm) long. Its ligules are 0.04-0.1 in. (1-2.5 mm) long.
The panicles measure 2-7.75 in. (5-20 cm) long, have numerous branches, retain an open quality and are generally nodding. The panicles bear from 3 to 8 drooping spikelets, each spikelet is 0.8-1.4 in. (2-3.5 cm) long. The glumes are awl-shaped. The lemmas are narrowly lanceolate, 0.04-0.06 in. (1-1.5 mm) wide, toothed, and sometimes hairy. They have slender, straight awns that are 0.4-0.67 in. (10-17 mm) long. Flowering occurs from May to June.
The seeds can germinate in the fall or in the spring; fall germination is generally more common. B. tectorum has a fibrous root system is finely divided. When a seed germinates in the fall, the developing root system is able to expand over the winter, giving the plant an increased ability to exploit available water and nutrients in the spring.
Ecological Threat
Bromus tectorum has the ability to draw down soil moisture and nutrients to very low levels, making it difficult for other species to compete. An increased cycle of fires favors annual species at the expense of many perennials. Due to its tendency to mature early and then dry out, it gains a competitive advantage through the promotion of fire. It is an agricultural, nursery and orchard pest.


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EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit

State Regulated List
   No Data for this state
   Troublesome or Common weed in one or more crops

Most Troublesome / Most Common Agricultural Weed List
This map identifies those states that consider this species either most troublesome or most common in at least one commodity. For more information, visit the MTMC project page.

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Commelinidae
Order: Cyperales
Family: Poaceae
Genus: Bromus
Subject: Bromus tectorum L.

Synonyms and Other Names

Other Common Names:
downy brome, early chess, military grass, thatch bromegrass

Related Scientific Names:
Anisantha tectorum L. (Synonym)
Bromus tectorum var. glabratus Spenn. (Synonym)


Plants - Grass or Grasslike