Wildflowers Found in Oregon
False Brome
Brachypodium sylvaticum -
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.
Impacts
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.
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