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: May to October. Seed-time: Seeds remain on the plant until winter, being usually scattered between December and March. Range: Labrador to Alaska, southward to New Jersey, Illinois, and Minnesota. In the Rocky Mountains to Arizona and in the
Sierra Nevadas to California. Habitat: Dry open ground; meadows and pastures.
A plant which has shown its weedy qualities chiefly in New England and in parts of Colorado, Indiana, and Ohio. It is a shrub, one to five feet tall, branching from the base, making a spreading, compact growth which chokes out all else. Young shoots are clothed in white down, but when mature the stems become hard, woody, and covered with hairy, ragged, grayish brown bark. These old "Hard-hack" stems are incredibly tough and turn the edge of the sharpest scythes. Leaves pinnately five- to seven-foliate, the leaflets pointed at both ends, a half-inch to an inch long, entire, with margins slightly revolute, gray-green with silky hairs. Flowers in terminal cymose clusters, numerous, bright yellow, about an inch broad, the five petals nearly round and exceeding the ovate calyx-lobes and the pointed bracts. Achenes twenty or more to a flower, small, light, hairy-coated, blown far and wide over crusted winter snow. (Fig. 150.)
Fig. 150. - Shrubby Cinquefoil (Potentilla fruticosa).
One way is to cut or burn off the tops before the leaves start in the spring, and then, with a strong team and a heavy plow, turn out the roots, drag them from the soil with a harrow, pile, dry for a few days, and burn. Some of the largest roots will prove too much for the plow and the harrow; such roots must be pulled by a horse with a chain, aided by a man with a crowbar. Or young and comparatively shallow roots may be knocked out of the ground with a pickax while the soil is still frozen. Farmers who have thus reclaimed Cinquefoil fields say that the land is left in excellent condition for crops, being apparently improved rather than exhausted by its weedy occupant. Some of these shrubby lots may not be worth so much expense and labor and should be given back to forest growth, which soon drives out the weed and would, in the end, prove a very profitable investment.
The keeping of Angora goats has been successfully tried, those animals browsing back the twigs and entirely preventing seed development; but there is probably more than enough Black Brush, as the shrub is called in Colorado, to supply all the goats in the country. On the whole, the best means of keeping out this very aggressive weed is not to let it get in; that is, whenever the white, woolly, young shoots appear, hand-pull them promptly, letting none mature to reproduce themselves by thousands and possess the land.