Fig. 223. - Wild Sweet Potato Vine (Ipomoea pandurata). X 1/4.
Time of bloom: June throughout the summer.
Seed-time: August until cut off by frost.
Range: Nova Scotia to Manitoba, southward to Virginia, Missouri, and Kansas. Habitat: Rich soil; fields, meadows, and waste places.
A most obnoxious weed, spreading chiefly by means of its long, creeping, cord-like roots, which at any part of their length may bud new plants. Stems smooth, slightly angled, slender, one to three feet long, twining about and over any plant within reach, robbing it of air and light while the roots below are starving it of food and moisture. Leaves alternate, halberd-shaped, with backward-pointing lobes at the base, on slender petioles. Flowers pink, sometimes nearly white, funnel-shaped, about an inch across, usually but one or two on each slender peduncle, but occasionally three or four; calyx not bracted at the base as in the following species, but there are two small scale-like bracts, some distance below, on the peduncle. Capsules globular, two-celled, usually four-seeded. Seeds dark brown, about one-eighth of an inch long, pear-shaped, rough, with one side flat and the other rounded; too frequently an impurity of other seeds. (Fig. 224.)
Sow clean seed. Put the ground under clean cultivation for two years; the infested land should be deeply plowed and as many as possible of the whip-cord roots harrowed out or raked out and destroyed, or they may be fed to pigs; but each bit left in the soil will start new growth and tillage must be so frequent and so thorough that no green leaves are permitted to feed these roots. Where it is practicable to grow alfalfa, this crop tends to smother the Bindweed with its thick cover and the frequent cutting checks leaf growth of the weed and prevents seeding. Or infested land may be broken up with the plow and hogs may be turned in - with snouts in working order - for the purpose of turning out and eating the succulent roots, of which they are very fond. Sheep pasturing on infested ground will also keep leaf-growth down and will starve the underground growth.
Fig. 224. -Field Bindweed (Convolvulus arvensis). X 1/3.