|Other names:||annual ragweed, ragweed, low ragweed, Roman wormwood, short ragweed, small ragweed, wild tansy, bitterweed, hog-weed, mayweed|
Plants are upright and bushy, growing to 3 ft tall. Leaves have long, prominent stems, are finely divided and are hairy on the upper surface. Seeds are displayed on spikes at the ends of branches. Seeds are viable in the soil for 5 years or more. Ragweed is a major cause of hayfever.