This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native and introduced. Biennial. Propagates by seed.
Time of bloom: August to October.
Seed-time: September to November.
Range: Nova Scotia to the Northwest Territory, southward to Pennsylvania, Tennessee, and Missouri. Habitat: Stubble fields, roadsides, and waste places.
Probably the most common of the Wormwoods; frequently a tenant of vacant city lots. Stem one to four feet tall, erect and strict, the branches rather short and held nearly upright. Leaves smooth on both sides, dark green, twice pinnatifid, with oblong to linear, toothed, and pointed segments, the lower with petioles, the upper sessile and with fewer lobes or occasionally quite entire; they are without odor unless bruised. Heads in short, crowded, axillary clusters, erect, sessile, about an eighth of an inch broad, the involucral bracts green with scarious margins, the central flowers only producing seed.
Hoe-cutting or hand-pulling of autumn plants; close cutting of flowering stalks before seed development. Infested stubbles should be given surface cultivation or be mowed before the heads mature.