Native Poisonous Plants
Death camas (Zigadenus venenosus)
Zigadenus venenosus, commonly called death camas or
meadow deathcamas, is a flowering plant in the genus
Zigadenus belonging to the Melanthiaceae. It grows up
to 70 cm tall with long, basal, grass-like leaves. The bulbs are
oval and look like onions but do not smell like onions. The
flowers are cream coloured or white and grow in pointed clusters,
flowering between April and July.
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Larkspur Delphinium nuttallianum
Larkspur is a native that grows at higher elevations. Fatal poisoning occurs mainly in cattle. When using herbicides on this and other poisonous species, care should be taken to keep grazing animals off infested areas until treated plants have totally expired. Herbicides increase sugar production in treated weeds making them more palatable. |
Purple Locoweed Oxytropis sericea
Flowers vary in color by species, with silky crazyweed having white flowers and Lambert crazyweed having purplish-pink flowers. All livestock species can be poisoned by eating crazyweed. Horses never recover once they are poisoned. Abortions in cattle and sheep are common from eating these plants. |
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Twogrooved milkvetch Astragalus bisulcatus
Members of this genus are poisonous, affecting cattle, sheep and horses. Twogrooved milkvetch contains both selenium and swainsonine,the alkaloid responsible for locoism. As little as 2 lbs. can cause acute poisoning in mature cows within a few hours after being eaten. Poisoning symptoms are respiratory problems and paralysis of the hind legs |
Western Waterhemlock Cicuta douglasii
Highly poisonous perennial that is found in wet areas and sometimes growing among cattails or along irrigation canals. One bite is fatal to humans and animals. Rubber gloves are recommended when handling this plant. Leaf veins that terminate at the bottom of leaf serrations identify this plant. It is often fatally mistaken for water parsnip or other edible members of this family. Numerous deaths are attributed to this species. After ingesting, violent death normally occurs within a half hour. |
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Western Whorled Milkweed Asclepias subverticillata
White flowers and milky latex sap identify this perennial species. Reproduces by seeds and horizontal underground roots |
White Locoweed Oxytropis sericea Flowers vary in color by species, with silky crazyweed having white flowers and Lambert crazyweed having purplish-pink flowers. All livestock species can be poisoned by eating crazyweed. Horses never recover once they are poisoned. Abortions in cattle and sheep are common from eating these plants. |
