Great Water Dock

Rumex hydrolapathum

Physical Characteristics

Rumex hydrolapathum is a PERENNIAL growing to 1.8 m (6ft). See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in flower from July to September, and the seeds ripen from August to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Wind. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil and can grow in water.

Distribution

Western Europe, including Britain, from Scandanavia south and east to Spain, Italy and S. Russia.

Habitats

Pond; Bog Garden;

Edible Uses

Edible Parts: Leaves Seed Edible Uses: Young leaves - cooked[2, 105, 183]. Seed - raw or cooked. It can be ground into a powder and used as a flour[102]. The seed is small and rather fiddly to harvest.

Medicinal Uses

Antiscorbutic Astringent Ophthalmic The root is antiscorbutic and strongly astringent[4]. It is harvested in early spring and dried for later use[4]. The green leaves are said to be an excellent application for ulcers of the eyes[4].

Known Hazards

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[238].