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 September.
Seed-time: July to November.
Range: Labrador to British Columbia, southward to Maine, Michigan, and Minnesota, and along the Rocky Mountains to central Mexico.
Habitat: Moist, rich soil; fields, low meadows, waste places.
This weed is tolerant of soil which is somewhat brackish and it often damages the hay crop from the salt-marsh meadows along the Coast. It has also made its way to Europe, where it is regarded with much dislike.
Taproot rather stout, penetrating the soil to a great depth. Stems tufted, slender, ascending, flexuous, grooved, smooth, and pale green, one to three feet tall, usually simple. Leaves narrow, lance-shaped, pointed at both ends, the sides often nearly folded together; petioles rather short. Racemes erect, the whorls very dense; pedicels scarcely exceeding the calyx-lobes, jointed near the base; calyx olive to reddish brown, the valves triangular-ovate, delicately veined, all tubercled. Achenes dark red, smooth and shining; frequently an impurity of clover and alfalfa seed, so extending the range of a most troublesome weed.
Means of control the same as for Rumex crispus. In well-tilled ground none of these large, deep-rooted weeds attain sufficient size to be very troublesome.