Common Ragweed—Ambrosia artemisiifolia

A native annual, ragweed is valuable to many kinds of wildlife, but it produces large amounts of pollen, causing hayfever in those with allergies. It can be found in fields, gardens, along roadsides and vacant lots.

ragweed plant
Grows upright, to 3 feet tall, with frequent branching. Agressive and persistent, the seeds remain viable for up to 80 years.

ragweed plant
Flowers are small and grow in slender, elongated spikes. They are green when young, then turn yellowish green or brown. Flowers July–November.

ragweed flower up close
Each flower is about 1/8 inch long. Male flowers produce a fine yellow pollen–each plant may produce up to 1 billion pollen grains.

ragweed seedling
Leaves up to 8 inches long, divided into many narrow, toothed segments, each segment pointed at the tip.

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Identification and Control Information

[Photos, left to right: Ohio State Weed Lab Archive, The Ohio State University,; Richard Old, XID Services, Inc.,; Steve Dewey, Utah State University,; Joseph M. DiTomaso, University of California - Davis,]