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 and by rootstocks.
Time of bloom: June to August.
Seed-time: August to October.
Range: Anticosti to British Columbia, southward to Georgia, Nebraska, and Arizona.
Habitat: Fields, roadsides, and thickets; frequently troublesome in vineyards.
A poisonous weed, but very graceful and attractive, growing usually in patches or colonies because of its extensive creeping, horizontal rootstocks, from which new plants are sent up at short intervals. All parts of the plant, even the rootstocks, are filled with an acrid, milky juice. (Fig. 218.)
Stems somewhat shrubby, one to three feet tall, smooth, very slender, branching at wide angles, reddish on the upper side where exposed to the sunlight, green beneath. Leaves opposite, ovate to oblong, entire, smooth and dark green above, somewhat hairy and paler beneath, acutely tipped, rounded or blunt-pointed at base, with short, often reddish petioles. Flowers in terminal and axillary cymose clusters, the corollas nodding, bell-shaped, with five recurving lobes, pale pink, marked with lines of deeper pink, fragrant; stamens five, inserted on the base of the corolla and alternating with five small triangular appendages below the throat and opposite the lobes. Ovaries two, distinct and free from the calyx forming twin follicles, round, slender, four or more inches long, smooth, curved, stuffed with many thin, flat, brown seeds tipped with tufts of fine white floss, by which the wind is enabled to give them wide distribution.
When colonies of the weed appear near house grounds or barn yards, they should be killed at once by the use of strong, hot brine or caustic soda. In field, pasture, or fence row, the spud or the scythe should be frequently used, beginning with the first bloom and repeating as new shoots appear, dry salt being used for the purpose of checking new growth. Rankly infested ground is most easily cleansed by breaking it up, exposing the rootstocks during hot summer weather.
Fig. 218. - Spreading Dogbane (Apocynum androsoemifolium). X 1/4.