Brazos County Herbarium

Brazos County Horticulture Extension

Perennial Broomweed, Broom Snakeweed

Gutierrezia sarothrae (Pursh) Britt. & Rusby

Asteraceae (Sunflower Family), Poaceae

Description

Perennial broomweed or broom snakeweed is a short-lived, perennial half-shrub ranging from 6 inches to about 2 feet tall. Many unbranched, erect stems originate from a woody base and die back when the plant goes dormant. The leaves are narrow and threadlike. The small yellow flowers are clustered at the branch tips from June to October.

Habitat

Perennial broomweed is widespread on dry ranges and deserts from California to Texas, south to Mexico and north to Idaho. Extreme infestations reduce forage production but may not indicate overgrazed ranges because broomweed populations fluctuate naturally. However, overgrazing does accelerate the plants growth and propagation.

Toxic Agent

Perennial broomweed poisons cattle, sheep, goats and swine. Some believe the toxic agent is a steroidal aponin. The plant may accumulate selenium when on high selenium soil. Perennial broomweed is most toxic at earlier growth stages, usually in late winter or early spring and on sandy soils. It is relatively nontoxic growing on clay soils. Cattle abort after eating as little as 20 pounds of fresh broomweed in 7 days. Cattle, sheep and goats have been killed by eating 10 to 20 percent of their body weight in perennial broomweed over 2 weeks.

Signs of Livestock Ingestion

Chronic poisoning signs include: Abortion; Stillbirth; Retained placenta; Weak offspring;

Acute poisoning signs include: Periodic, thick nasal discharge; Crusting and sloughing of the skin of the muzzle; Listlessness; Loss of appetite and weight; Rough hair coat; Occasionally, dark brown or reddish urine;

Frequent urination with diarrhea in the early stages changes to constipation with large amounts of mucous. Pregnant cows often have periodic vulvar swellings and premature udder development.

Management Strategies

Do not graze gestating livestock on sandy soils during maximum perennial broomweed growth (late winter and early spring). Proper range management practices that improve range condition may help limit perennial broomweed population densities and livestock consumption. Carefully watch pregnant cattle grazing perennial broomweedinfested pastures. If udders develop prematurely, vulvas swell or abortions occur, move the herd to a perennial broomweed-free pasture. Chemical control may be costeffective when populations are dense enough to reduce forage production. Herbicide treatments for perennial broomweed include aerial or ground broadcast applications of Escort® at 0.0625 ounce a.i./acre in the spring when weeds are less than 4 inches high. Tordon 22K® may be used during and after full flower stage in the fall at 0.25 to 0.5 pound a.i./acre. To reduce reinfestation, follow chemical treatments with proper range and livestock management programs.

Images

[Show slideshow]

Department of Rangeland, Wildlife, and Fisheries Management

Web Site Maintenance: Megan.Clayton@ag.tamu.edu