False brome (Brachypodium sylvaticum) is a highly invasive bunchgrass that has been found in only a few, isolated locations in Multnomah County. This weed is particularly troublesome in Oregon due to its ability to spread right through the shaded, understory of our native forests. In the southern and mid-Willamette Valley this perennial, native to Europe, Asia and North Africa, has completely dominated forest understory and open habitats at alarming rates, and is driving out native plants and creating a blanket of vegetation consisting of only itself. It spreads by seed and can quickly outcompete native plants and ruin pasture as it is largely unpalatable for grazing.
False brome often spreads through roadsides and along trails where seeds can hitch an easy ride, before taking off into adjacent properties. The seeds also travel easily down creeks and streams becoming deposited on shorelines. It can tolerate a very wide range of conditions, growing in both shade and full sun, and in both very moist and dry soils. By keeping an eye out for this weed and taking quick action to control it we can make sure it doesn’t dominate our native forests, pastures or timberlands.
False brome can be hard to identify from native perennial grasses though it has two distinguishing characteristics that when combined help with identification.
The first is the small hairs or “fuzz” covering and sticking out from the leaves and stems. This fuzz gives the tops of the leaves an almost velvety feel.
The second critical identifying feature is its droopy flower/seed stalks with completely stalkless spikelets (spikelets are attached directly to the flower/seed stalk). It has broad (a quarter to a third of an inch wide), flat, droopy leaf blades and also is bright green in color which remains after most other grasses and natives have gone dormant (through fall and into winter).
False brome grows in large, “squatty” clumps or bunches 18 inches to three and a half feet tall. Seed stalks, which also droop considerably, can be seen from spring through fall. Seeds ripen in July and stay on the plants through November or December.
If you think you have found this plant please report it immediately. This plant is on our EDRR list, and we provide free control. Report a sighting!
To see more photos of false brome click here