Smooth Brome (Bromus inermis)
Grass Family (Poaceae)
Austrian brome, brome, bromegrass, Hungarian brome, Russian brome, smooth bromegrass.
Origin and Distribution:
Smooth brome was introduced as a forage grass into California from Europe in the early 1880's. It is still cultivated in some parts of the U.S., and has become naturalized in the northern half of the country, as well as in southern Canada. It is relatively common in Ohio, and can be found in fields, waste places and roadsides. Smooth brome tolerates drought and extreme temperatures, and can grow in a variety of soil types, preferring well-drained, fertile soils.
Smooth brome is a sod-forming, perennial grass, distinguished by long, slender, bronze- or purple-tinted flower clusters that make up the flower head. This species spreads by seeds and dark-colored rhizomes (horizontal underground stems).
Smooth brome forms an extensive underground system of rhizomes (horizontal underground stems) and roots. Rhizomes are covered with a dark brown to black, scaly sheath. Roots are produced at the joints (nodes) of the rhizomes.
Stems are erect, leafy, round, and mostly smooth, and can grow 1 to 3 1/2 feet tall (sometimes up to 5 feet).
Leaves are rolled in the bud. The LEAF BLADE (free part of the leaf) is 4 to 16 inches long and 1/5 to 1/2 inch wide. Blades are generally smooth, flat and pointed, with rough margins. Some blades have a light green mark in the shape of a "W" near the middle. Blades tend to point upwards. The LEAF SHEATH (part of the leaf surrounding the stem) is round and usually smooth. Margins of the sheath are fused except for a notch at the top. The ligule (projection on the inside of the leaf at the junction of the blade and sheath) is membranous and relatively short (1/32 to 1/16 inch). AURICLES (appendages at the top of the sheath) are usually absent, but if present, are very short (1/50 inch long) and rounded.
Flowers occur in smooth, slender clusters within a branched flower head, 4 to 8 inches long, at the top of the stem. Branches of the flower head are spreading when young, but become erect and aligned with the stem at maturity. Each flower cluster is approximately 1 inch long, and may be tinged with bronze or purple.
Fruits and Seeds:
Seeds are 3/8 inch long, narrow and golden or tan.
Smooth brome may be confused with quackgrass (Elytrigia repens). However, smooth brome lacks the prominent claw-like appendages (auricles) that clasp the stem at the top of the sheath in quackgrass.
Smooth brome flowers from late May to September. It produces a prolific amount of seed, which can be spread by wind, water, birds and mammals. Evidence shows that seeds can survive passage through the digestive tract of animals. This species can also spread rapidly through rhizome production. Smooth brome is extensively used as a forage grass, because it produces large amounts of high quality forage early and late in the season, and it resists trampling. This species is also planted along roads and banks to control erosion. Problems occur when the grass spreads from desired areas or persists after cultivation, sometimes overrunning fields, lawns and even woods. Smooth brome is also threatening native grassland and wooded habitats, especially in Canada.
Facts and Folklore:
Smooth brome was first cultivated as a forage grass in Hungary.