AppearanceAmbrosia artemisiifolia is an annual. It blooms in the late summer and it can grow up to 4 ft. (1.2 m) tall.Foliage Stems and leaves are blue-green and covered with fine hairs. Leaves divided and bottom sides covered in fine hairs, giving a gray appearance.Flowers Flowers inconspicuous, yellowish-white, and found on terminal branches.Fruit Fruits are yellowish to reddish brown, woody, spined, ridged, and crow like in appearance. Seeds are 0.12-0.16 in. (3-4 mm) long.Ecological Threat This plant is common throughout the United States and causes hay fever in many people. It is commonly found along ditches and waste areas. It is not highly competitive in crops or rangeland. Native to all U.S. states except Hawaii and Alaska.Herbicide Resistance Populations of this plant exist in the United States that are resistant to ALS inhibitors (B/2),Photosystem II inhibitors (C1/5), PPO inhibitors (E/14), Glycines (G/9)