This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Perennial. Propagates by seeds. Time of bloom: August to October. Seed-time: September to December. Range: Maine to Ontario and Wisconsin, southward to Virginia and Kentucky. Habitat: Dry soil; meadows, roadsides, and waste places.
Meadows and pastures infested with this weed are in a bad condition, for as green forage it is worthless, and the hard, woody stems that have given it the name of Steelweed dull or break the mowing knives and "cut the grade" of hay that is intended for market.
Stem one to three feet high, smooth or nearly so, diffusely branched, spreading and bushy. Leaves rather thick and rigid, the lower ones spatulate, one to three inches long, tapering to a slightly margined petiole, sometimes sparingly toothed; the upper ones narrow lance-shaped, sessile, entire, becoming linear and awllike as they near the summit. Heads very numerous, racemose along the upper side of the spreading branches; they are hardly a half-inch broad, with fifteen to twenty-five white or pinkish rays; bracts of the involucre rather thick and awl-like, green-tipped. The blossoms secrete nectar of a fine, limpid quality, and the plant is a favorite with bee-keepers. Achenes small, gray, finely hairy, the pappus white; they are widely wind-distributed. (Fig. 301.)
Westward to Minnesota and Missouri, this plant gives place to a near relative, the Hairy Heath Aster (Aster ericoides var. pilosus, Porter), very like it in appearance and habits except that the hard stems and the small, pointed leaves are clothed all over with fine, soft hair.
Cultivation of the ground, fertilizing heavily and tilling very thoroughly before reseeding with clover and grasses. Sheep will eat the weed while it is young and will do good service in keeping it down in pastures.