Introduced. Biennial. Propagates by seeds. Time of bloom: July to September. Seed-time: August to October. Range: Maine and Ontario to Virginia, westward to Michigan. Habitat: Pastures, roadsides, fence rows, and waste places.
Stems stout, erect, strongly ridged, branching, beset with spines, three to six feet tall, springing from a stout taproot often more than a foot long with many feeding rootlets. Root-leaves of the previous year's growth tufted in a broad and very flat rosette, oblong to lance-shaped, obtuse, tapering at the base, scallop-toothed, the surface wrinkled and deep green except the veins and midrib, which are nearly white and beset with spines; stem-leaves opposite and often united at the base, forming cups which retain water, the rigid midribs spiny on the under side. Flowers in large, dense, solitary heads, sometimes nearly four inches long and two inches in thickness, protected by long, upcurving, spiny involucral bracts and lifted on long, spiny peduncles, terminal and axillary; corollas lilac or pinkish purple, tubular, four-lobed, fragrant, each subtended by a chaffy bract tapering to an awn longer than the flower; stamens four, inserted on the tube of the corolla; ovary inferior, one-celled. Some flower communities progress in their bloom from the base upward, others from the top downward; but Teasels girdle the middle of the heads with the first flowers and proceed both ways, though the last flowers of September are likely to be as round as clover-heads and produce all their blossoms at once with an air which says, "Time's up ! All out I" Fruit a hard, wedge-shaped, square, black, grooved achene, about a quarter-inch long. (Fig. 282.)
Fig. 282. - Wild Teasel (Dipsacus sylvestris). X 1/8.
Cut first-year rosettes from the roots with sharp hoe or spud, in autumn or early spring. Flowering stalks should be pulled or closely cut before the earliest heads ripen seed.