Docks and sorrels of the genus Rumex, comprising approximately 200 species, are temperate-climate weeds widely dispersed throughout the Northern Hemisphere. There are 20 species found in the northeastern region, and 24 species in California. Native species of Rumex are found most commonly in the western half of the United States. Curly dock (or yellow dock), Rumex crispus, is a Eurasian introduction that has spread across the continent. Similarly, broadleaf or bitter dock, R. obtusifolium, is of European origin. Curly dock is found throughout the Great Plains and west of the Continental Divide. It does best in deep, moist soil, and may be found at altitudes from 100 to 8,000 feet. It may be dense in low, moist, areas.

Docks belong to the family Polygonaceae, which has several members of economic value as edible commodities. Seeds from buckwheat and green buckwheat can be ground into flour, and may be useful for wheat-intolerant persons. The seeds are also used for brewing. The petioles (stalks) of rhubarb are edible whereas the leaves are not, because of high levels of oxalic acid. Both rhubarb and monk's rhubarb have previously been used medicinally in Europe. The leaves of docks are generally edible, although some are rather bitter because of tannins and oxalates. When grazed on in excess, some docks have resulted in livestock loss, although poisoning has not been a problem with humans. Curly dock is considered the best tasting of the varieties of Rumex. Curly dock and bitter dock roots have been used by the Chippewa Indians in poultices for itching and skin eruptions.

Curly dock is a perennial with a large taproot. Stems are 2 to 4 feet high, dying back each fall, with new stalks arising in the spring. The lance-shaped leaves are blue-green to dark green, with a smooth edge that is wavy or crimped. The leaves alternate up the stem, with a basal rosette of large leaves that may be up to 12 inches in length. It reproduces only by seed. The flowers of most Polygonaceae are small and pollinated by a variety of flies and bees. Flowers of Rumex are pendulous, greenish, without petals, and wind-pollinated. Flowers of curly dock are initially yellowish green, turning rosy, and ultimately a dark reddish brown, stalks of which can be identified from a great distance in late summer. The seeds are small and surrounded by three wing-like vanes one-eighth to one-quarter inch long.

In distinction to many other weeds, Rumex species pollinate in late spring to early (vs. late) summer. Pollination is most intense from late April through May, but may persist into the summer. In California and southern Florida, dock may pollinate all year long, or for many months, at least. Most species of Rumex produce abundant pollen. In the height of anthesis, counts may approach those seen with grasses. The allergenic impact of Rumex species is probably greater than appreciated, but its importance is underestimated because of overlap with grass pollination.

Adapted from: Annals of Allergy, Richard Weber, MD,

June 2001