Copperweed is a perennial that may reach a height of 1.5 meters. A large number of stems grow from the crown; each has many narrow leaves. Small, flowering heads turn orange or yellow when mature.

When and Where It Grows
Copperweed grows along streambeds or gullies where moisture is plentiful and the soils are usually high in salt. It starts growing early in the spring. Flowers appear during July and August.

How It Affects Livestock
Cattle are more susceptible to copperweed poisoning than sheep. Ingestion of 1 1/2 kg of copperweed or an amount equal to 0.5 percent of the animal's weight may cause death. Poisoned cattle die in 24 to 28 hours. Poisoned sheep may linger 1 to 3 weeks before dying. Cattle and sheep generally graze copperweed when other feed is scarce. Cattle are more commonly poisoned and they are likely to eat the plant in the fall when they are being trailed from summer range. Sheep are occasionally poisoned in the fall and winter by eating dry leaves that have fallen to the ground.

Copperweed contains an unidentified toxin that is dangerous at all times. Toxicity reaches a peak when the plant matures. Leaves and stems are equally toxic.

Signs and Lesions of Poisoning