Catchweed Bedstraw: Galium Aparine L

PNW 388 • January 1992 Catchweed bedstraw Galium aparine L.

L.C. Burrill

Catchweed bedstraw RELATED (Galium aparine L.), also called bedstraw or cleavers, is a native SPECIES annual with weak, climbing, NORTHERN BEDSTRAW or twining stems, up to 6 feet (Galium boreale L.), which is long (figure 1). Whorls of six native to the United States, to eight narrow single-nerved differs from catchweed bed- leaves are attached to square straw in four ways: stems (figure 2). Both stems and leaves have short back- • it’s a perennial from rhi- ward-turning bristles that zomes; Figure 2.—Leaves are in whorls • it has leaves that are three- cause the plants to cling to around square stems. other objects. nerved and four to a whorl; • it has stems that are more This clinging characteristic to the hair or wool of passing erect and don’t cling; and minimized matting when the animals or people’s clothing. • hairs on its fruits may be plants were used as a mattress straight, curled, or absent, filling, giving rise to the name Flowers are small, white, four- but not hooked. bedstraw. These same bristles parted, and borne on short also aid dispersal by attaching CORN BEDSTRAW (Galium branches in the leaf axils tricorne L.) is an annual with (figure 3). Fruits of two nearly five to eight leaves per whorl. round halves, with one seed Leaves have one nerve. Stems per half, are covered with fine are under 2 feet long, and hooked hairs. fruits are rough but not hairy. Catchweed bedstraw and related plants are increasing as problems in cropland in the Pacific Northwest. The pri- mary problem isn’t competi- tion with crops but difficulty in harvesting when bedstraw becomes tangled with the crop or equipment. The plant is a nuisance when the fruits attach to clothing or to fur of pets. When heavily Figure 3.—Small white flowers are borne on short branches in leaf axils. matted in wool of sheep, Figure 1.—Catchweed bedstraw is a bedstraw reduces the value of weak-stemmed annual that will cling Larry C. Burrill, Extension weed to other plants. the wool. scientist, Oregon State University.

A Pacific Northwest Extension Publication • Oregon • Idaho • Washington Corn bedstraw is native to crop seed, machinery, and special controls have been Europe. livestock. Annual species are found or are still being pur- easy to pull from the soil to sued. control a few plants in fields CONTROL or ornamentals. Herbicide registrations change frequently; therefore, this Efforts to prevent bedstraw Rhizomes of northern bed- publication doesn’t contain from invading cropland, straw may be killed or weak- specific herbicide uses. Regis- gardens, or ornamental ened by repeated cultivation, tered herbicides are summa- plantings deserve attention but this isn’t practical in most rized each year in the Pacific because the plant becomes cropping systems. Northwest Weed Control Hand- established first in unculti- book. vated areas such as fence BIOLOGICAL. No insects or rows, under trees, and in disease agents are known to In addition, detailed instruc- thickets bordering fields. control this or related species. tions for herbicide use are Currently, bedstraw doesn’t provided on herbicide con- These plants must be con- cause enough economic loss to tainer labels and in other trolled to reduce the number warrant a search for biological literature provided by herbi- of seeds available for spread control agents. cide manufacturers. into fields. Ways of moving bedstraw seed that can be CHEMICAL. In a few crops, stopped include contaminated current weed management seems to prevent bedstraw establishment. In other crops,

Photos are by the author.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the Oregon State University Extension Service, O.E. Smith, director; Washington State University Cooperative Extension, Larry G. James, interim director; the University of Idaho Cooperative Extension System, LeRoy D. Luft, director; and the U.S. Department of Agriculture cooperating.

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