An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press

SEEPWILLOW BACCHARIS,seepwillow,waterwally

Illustration

SUNFLOWER FAMILY-Compositae

SEEPWILLOW BACCHARIS-Baccharis glutinosa Pers.

DESCRIPTION-Straggling shrubs with willowlike leaves and several clustered stems 3 to 10 (or 13) feet high, reproducing only by seeds. The stems are woody below, l/2 to 1 inch diameter at base, with green, prominently grooved branches. The bark on the old stems is dark gray and furrowed. The numerous leaves are alternate, bright green, leathery, lustrous from sticky resins, and have a rather pleasant odor, narrowly lanceshaped, 1 1/2 to 6 inches long, 1/4 to 2/3 inch broad, and with smooth margins and small but definite teeth.

The small, unattractive, greenish yellow flowering heads, about 1/5 inch diameter, occur in dense clusters at the tips of the main branches only, and are not scattered in the leaf axils. Male and female heads grow on separate plants. These plants are clearly distinguishable at the flowering and fruiting stages. The narrowly oblong seedlike achenes, 1/25 to 1/16 inch long, are strawcolored to greenish brown, with 5 white longitudinal ribs, and at one end bearing a thin tuft of fine, silky whitish hairs, 1/5 inch long.

DISTRIBUTION-A native shrub of watercourses, semipermanent irrigation canals or ditches, and streambanks. Very common along the Colorado River drainage from Apache to Mohave counties, and river bottoms, disturbed areas, and depressions where water collects; sometimes in moist soil at ends of cotton rows; throughout southern Arizona in the desert and desert grassland ranges; from 100 to 5,700 feet elevation; flowers from March to December.

Seepwillow baccharis is unpalatable, and worthless as forage. It often forms dense thickets along streambeds, and in water-conscious Arizona is considered to make excessive use of precious water. It also may clog stream channels, and cause flash floods to back up and innundate adjacent lands.

Because of its rapid growth and deep fibrous roots, it has been used extensively in erosion control plantings along watercourses, and is propagated from cuttings. It is interesting to note that seepwillow baccharis, like tamarix, is now considered an objectionable weed due to characteristics which were considered virtues at one time.

Copyright (c) 1972 The Arizona Board of Regents



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