Skip to content

Bromus madritensis

Scientific Name: Bromus Madritensis
Common Name: Compact Brome, Spanish Brome

Line Drawing:

Morphological Description:
Each plant has several stems growing from an erect or slightly spreading base; the stems have narrow, short, flat, hairy, prominently-veined blades and a hairy sheath
Grows solitary or  in clumped stems to maximum heights between 10 and 50 centimeters
Spikelets with longawns which vary in color from green to distinctly purplish-red

Habitat & Basic Biology (life history, dispersal abilities):
Bloom period is in February through March
Able to germinate after precipitation event of 1 cm
Does not produce dormant seed
Does not maintain a soil seed bank, but exhibits early and uniform germination
Can reach density of over 6000 plants m-2
Reproduction is solely by seed. Each plant produces approximately 75 seeds of which less than 2 percent will carry over into the following year and remain viable thereby creating a relatively short-lived seed bank. Mature seed remains mostly dormant through the hot, dry summer; germination is highest in the fall

Functional traits (photosynthetic rates, phenology, etc.):
Monocot, annual herb

Distribution (geographic range):

Control Methods:
Mechanical – can be pulled by hand before early spring
Moderate livestock grazing may be effective as long as native plants are not affected
Fire – susceptible to burning if conducted before seeds mature
Growth regulator herbicides of aminopyralid and picloram have been proven to reduce seed production

Evolution (of traits in novel range):
Elevated atmospheric CO2 levels create physiological response in B. madritensis, measured as stomatal conductance. Physiological traits may evolve more rapidlythan morphological traits.

Performance of invader in CA (interactions with species native to S. CA):
Produces persistent fine fuels that have been linked to the increase frequency and intensity of fires in the south west US
The abundance of B. madritensis increased sharply in the 1970’s, especially in the Mohave Desert
In California chaparral, fall germination of foxtail chess gives the grass a competitive advantage over shrub seedlings

Natural enemies:
One possible enemy is the Barley yellow dwarf virus RPV strain

List of references:
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of Calif. Herbaria. [web application]. 2014. Berkeley, California: The Calflora Database [a non-profit organization]. Available:   (Accessed: May 05, 2014).

“Field Guide for Managing Red Brome in the Southwest.” Bromus Rubens, Bromus Madritensis. USDA, Dec. 2012. Web. 05 May 2014.
A Field Guide providing information on control methods for Bromus Madritensis.

Grossman, Judah D. “Contemporary Evolution of an Invasive Grass in Response to Elevated Atmospheric CO2 at a Mojave Desert FACE Site.” Ecology Letters 17.6 (2014): 710-16. Wiley Online Library. Web. 6 June 2014.
Grossman and colleagues tested the evolution of B. Madritensis in response to elevated CO2 levels.

Major, Jack, and E. K. Woodford. “Weed Control Handbook.” American Midland Naturalist 67.2 (1962): 509. Weed Report. UC Davis. Web. 6 June 2014.
An excerpt from the book Weed Control in Natural Areas in the Western United States.

Simonin, Kevin A. 2001. Bromus rubens, Bromus madritensis. Simonin, Kevin A. 2001. Bromus rubens, Bromus madritensis. In: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [2014, May 5].
The Fire Effects Information System is an online collection of reviews of the scientific literature about fire effects on plants and animals and about fire regimes of plant communities in the United States.