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false brome (Brachypodium sylvaticum (Huds.)Beauv.)
ODA rating: B

Oregon false brome distribution
Other common names
slender false brome

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Images courtesy of Glenn Miller, Oregon Dept. of Agriculture.

If images are downloaded and used from the ODA web site please be sure to credit the photographer.

Perennial grass; forms short "squatty" bunches. Stems hollow with broad, flat one quarter to one third inch wide lax leaves and a leaf sheath open to the base. Leaf color a bright green that often remains through fall and part of winter. Leaf margins and lower stems hairy; ligules membranous . Flowers born in a true spike that droops noticeably, and spikelets with short or no stalks. False brome plants appear to be self-fertile producing few to a couple hundred seeds per plant. Isolated plants are observed to produce viable seeds and become new weed epicenters complicating control efforts. Seed movement by wildlife is locally important with both birds and small mammals transporting seeds. Deer and elk also are important vectors of localized spread. Long-distance dispersal is predominantly through logging activities, roadside maintenance equipment and recreational activities within infested areas.

False brome can quickly become the dominant plant species in forest understories, demonstrating great shade and drought tolerance. It is able to grow in a wide variety of habitats and competes strongly for early season moisture. Its presence in commercial timberlands creates a perfect environment for rodents which damage tree seedlings. It can dominate oak savannah habitats and can be expected to severely restrict native oak regeneration. This weedy grass is also a serious threat to natural areas. There is concern from naturalists and native plant enthusiasts because of the ecological impacts brought on by brome invasion. The economic impact has received less attention and has been limited to private timberlands. Many acres of private timberland receive initial herbicide treatments to remove grass and other vegetation regardless if they are brome infested or not, therefore, no additional costs are attributed to false brome. The same cannot be said of public lands and it is on these where the greatest potential for economic harm exists. A secondary economic concern may involve false brome toxicity to livestock. The endophyte fungus Epichloe sylvatica has been identified in North American false brome populations. Existence of endophyte fungi in forage grasses has been linked to negative health effects in sheep and other livestock. Currently, no false brome pastures have been identified in Oregon but the threat may increase in the future. Land managers in the Pacific Northwest should be on the lookout for this invasive plant and be aware of its aggressive potential.

This exotic perennial is native to Europe, Asia and North Africa, but is invading habitats in western Oregon, and elsewhere in our region at an alarming rate. The earliest record (OSC) of the species in North America is a 1939 collection from near Eugene in Lane County, Oregon. By 1966, the species grew in at least two large colonies in the Corvallis-Albany area of Benton County, Oregon, where it was apparently thoroughly naturalized (Chambers 1966, Madrono 18: 250-251).

Distribution in Oregon
Oregon is the epicenter for false brome in the U.S. with smaller outbreaks in California and Washington. Limited evidence suggests that false brome can survive in the drier colder portions of Oregon. The Klamath, Ochoco, Blue Mountains and Siskiyou mountains may all be susceptible at various levels.

Biological controls
No approved biological control agents are available at this time.