Brazos County Herbarium

Brazos County Horticulture Extension

Western Ragweed , Cuman Ragweed, Perennial Ragweed, Common Ragweed

Ambrosia psilostachya DC.

Asteraceae (Sunflower Family)

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Description

Western Ragweed is a native, warm-season perennial in the Sunflower family. A common Texas plant, it is also called Perennial Ragweed. Western Ragweed is rhizomatous and can reproduce through vegetative tillers that come from the parent plant. The plant grows from long rootstock, with stout, many-branched stems that can reach heights of 12 to 72 inches or 0.3 to 1.8 meters. The leaves are thick, gray-green, and hairy or bristly. They are 2 to 5 inches long and have deep serrations along the margins. The serrations are sometimes pointed, sometimes rounded. The plant flowers from late summer through fall. The seeds of Western Ragweed are borne along a central stem that grows 2 to 6 inches long at the top of the plant. The seed clusters are chaffy (like grain husks), becoming pointed and bristly with maturity. This plant provides good grazing for wildlife and poor grazing for livestock.

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Habitat

Western Ragweed grows mainly on disturbed sites, dry rangelands, and hillsides. It is a common rangeland plant across all regions of Texas.

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Images

Department of Rangeland, Wildlife, and Fisheries Management

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