Oregon State University Extension Service



Summer annual, with a composite (sunflower) type flower. Stems are whitish with narrow needle-like spiny leaves. Tends to like alkaline soils.


Has been found to be a problem in range, pasture, and cropland. The tough spiny plant is avoided by livestock. It is a heavy seed producer, and forms dense stands on areas favorable to its growth.

Chemical Control

Must be sprayed in the seedling stage (less than 3 inches in diameter). Spray applications must be timed correctly with seeding size. Specific recommendations for your site can be obtained from your local weed control supervisor, or chemical consultant.

Source URL: https://extension.oregonstate.edu/crop-production/field-crops/spikeweed