Skip to content

Western Ragweed

Photo by James Leiker

Common Name: Western Ragweed

Scientific Name: Ambrosia psilostachya

Family: Aster

Longevity: Perennial

Height: 1 - 2 feet

Bloom Period: July, August, September, and October


Description: Erect stems are branched. Leaves are deeply lobed and rough to the touch. Small, green flowers are inconspicuous. Male flowers, with yellow pollen, appear on stalks at the top of the stems. Female flowers are hidden in the axils of the upper leaves.

Comments: For people with hay-fever, ragweeds are a serious problem. Pollen, produced by the plants, is carried great distances by the wind. In pastures, ragweed is mostly ignored by cattle, but this plant has great ecological value for wildlife. Abundant and nutritious seeds remain available to wildlife throughout the winter. Moth larvae eat the foliage, as do numerous grasshopper species. These insects are important food for young grassland birds. Western Ragweed is common statewide.