(a.k.a. Crazyweed)

Locoweeds, Point locos,

Peavines Astragalus spp.

Fabaceae (Pea family)

There are many species of locoweed in Arizona, perhaps hundreds. Considered to be a low-growing, perennial herb, the leaves pinnately compound into numerous linear to oval leaflets. Flowers are said to vary in color, white to purple, by species but emerge from a leaf less stalk (from the center of the plant) and form a spear-like cluster of blooms. The kidney shaped seeds form in a tough, pea-like pod.

Long thought to be a joke or a point of humor, locoweeds (and their relatives) are no laughing matter, but are toxic to all classes of livestock in varying degrees. Horses are usually affected the most and will not recover if their poisoning has been of a chronic nature.

According to literature supplied by Kim McReynolds, Cochise County Range Management Specialist, there are three distinct groups of toxic species within the Astragalus genus.

Selenium: The first group is associated with selenium-rich soils. Selenium smells like garlic. These plants have the ability to concentrate selenium at toxic levels to animals: Two grooved milkvetch (5/8 lb. can be fatal to sheep within 30 minutes), Narrowleaf poisonvetch, Gray- AEs milkvetch.

Stinking Vetch Loco: This second group causes locoism (neurological symptoms ranging from incoordination, visual impairment, depression, unpredictable behavior, emaciation and eventual death) in livestock. All plant parts are toxic. Two indolizidine alkaloids (swainsonine and swainsonine N-oxide) are responsible for locoism in animals.

These plants cause locoism in animals: Specklepod loco. White Point, Purple Point loco. Two grooved milkvetch. Earless loco, Wooly loco. Sheep loco, Wooton loco, Silverline loco.

Nitro compound: The third group of astragalus species includes Timber milkvetch and Red stemmed peavine. Lactating sheep and cattle are the most susceptible group to poisoning. Horses have a low death rate but after recovery, they are only fit for minimal usage thereafter.

For immediate concerns about animal behavior in regards to any of the above suspected plants, consult your local vet. Animals will not normally choose to eat any of these plants if other forage is available. However, if an animal has been chronically exposed to loco weeds, it can become addicted and will seek the plants when grazing. Prevention and early diagnosis will save the lives of many livestock. Horses do not recover well.

For proper identification of any suspicious plants, submit plants with flowers to Kim McReynolds at the local Agricultural Extension Office.