Rumex obtusifolius, commonly known as broad-leaved dock, bitter dock, bluntleaf dock, dock leaf or butter dock, is a perennial weed, native to Europe but can now be found in the United States and many other countries around the world.
Rumex obtusifolius is easily recognizable by its very large leaves, some of the lower leaves having red stems. The edges of the leaves are slightly "crisped" or wavy. The foliage of the plant can grow to about 18 inches in height. The stems have nodes covered by an ocrea, a thin, paper-like membrane - a characteristic of the Polygonaceae family.
Large clusters of racemes contain green flowers that change to red as they mature. They are held on a single stalk that grows above the leaves and blooms June through September. The seeds produced are reddish-brown.
Seedlings can be identified by the oval leaves with red stems and rolled leaves sprouting from the center of the plant.
Rumex crispus - curly dock - is very similar in appearance but with thinner and wavier leaves. In more detail, the calyx of curly dock has smooth margins while the calyx of broadleaf dock has horned margins.
Medicinal uses of the herb
Other historical uses
Broadleaf dock is considered a weed and is slightly poisonous. It is designated an "injurious weed" under the UK Weeds Act 1959. Livestock have been known to get sick after feeding on it. But eradicating the plants is difficult. The perennial plant can have a deep taproot reaching 5 feet down. Also, the milk of the plant has been known to cause mild dermatitis.
Seeds have toothed wing structures, allowing them to be dispersed by wind or water, and also allow them to attach to animals or machinery to be spread great distances. They can lie dormant for years before germination, making vigilant pulling or tilling essential.
First year plants can seed, making early detection important for eradication.
The main weaknesses of Broadleaf are its poor competition, crowding causes flowering to be delayed for up to three years, and its susceptibility to disturbance. Frequent tilling will disrupt the roots and kill the older plants and seedlings. The plant also thrives in moist environments and improved drainage can also help control its growth.
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- Rumex. Yellow dock, Curled dock. Rumex crispus, Rumex obtusifolius. | Henriette's Herbal Homepage
- Eliot, George (1859). Adam Bede (Modern Library, 2002); p93-94.
- "List of Invasive species in the Great Lakes Great Lakes United / Union Saint-Laurent Grands Lacs". Retrieved 2009-02-07.