Flowering Aug–Nov. Gardens, fields, stream banks, around ponds, trash heaps, sometimes volunteering from past plantings; 10–300(–1500) m; introduced; Ont.; Ariz., Ark., Fla., Ga., Ill., Kans., Ky., La., Mass., Mich., Miss., Mo., N.Y., N.C., Ohio., Pa., S.C., Utah, Va.; Asia (e Himalayas); introduced also in West Indies, Pacific Islands (Hawaii).