Herb: Great Water Dock

Latin name: Rumex hydrolapathum

Family: Polygonaceae (Buckwheat Family)

Medicinal use of Great Water Dock:

The root is antiscorbutic and strongly astringent. It is harvested in early spring and dried for later use. The green leaves are said to be an excellent application for ulcers of the eyes.

Description of the plant:


180 cm
(6 feet)

July to

Habitat of the herb:

Near ponds and streams, also in shallow water, avoiding acid conditions.

Edible parts of Great Water Dock:

Young leaves - cooked. Seed - raw or cooked. It can be ground into a powder and used as a flour. The seed is small and rather fiddly to harvest.

Other uses of the herb:

The roots contain tannin. In cultivated plants, those grown on dry land contained 6 - 8% tannin whilst those grown in water contained 12.4 - 21.6%. The dried and powdered root makes a good tooth cleaner. Dark green to brown and dark grey dyes can be obtained from the roots of many species in this genus, They do not need a mordant.

Propagation of Great Water Dock:

Seed - sow spring in situ. Division in spring.

Cultivation of the herb:

Near ponds and streams, also in shallow water, avoiding acid conditions.

Known hazards of Rumex hydrolapathum:

Plants can contain quite high levels of oxalic acid, which is what gives the leaves of many members of this genus an acid-lemon flavour. Perfectly alright in small quantities, the leaves should not be eaten in large amounts since the oxalic acid can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.

Plant information taken from the Plants For A Future.