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Home > Weeds > Ragweed

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 ragweed plant ragweed flower up close ragweed seedling
Grows upright, to 3 feet tall, with frequent branching. Agressive and persistent, the seeds remain viable for up to 80 years. Flowers are small and grow in slender, elongated spikes. They are green when young, then turn yellowish green or brown. Flowers July–November. 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. 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 (each will open in a new window)


[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,]

It is the policy of the State of Maine to minimize reliance on pesticides. The Maine Department of Agriculture and the Maine IPM Council encourage everyone to practice integrated pest management and to use pesticides only as a last resort. The mention of pesticides in the fact sheets linked to these pages does not imply an endorsement of any product. Be sure that any product used is currently registered and follow all label directions.