Rumex maritimus aka Maritime Dock

Rumex maritimus, or golden dock, is in the knotweed family. This family has the name Polygonaceae. Its native range covers subarctic and temperate parts of Eurasia. The RHS lists Britain and Ireland as native areas too. It grows as an annual, though Kew records biennial plants too. Plants reach about 1.6 feet (0.5 metres) tall. It grows in temperate regions on damp, open ground. Wild sites include lake shores and the edges of reservoirs. It also grows in ponds that have dried out.

Golden dock grows on bare mud, and sometimes in damp grass. It grows near the coast and withstands exposure to sea air. Its flowers bloom from June to September. Each flower has both male and female organs. Wind moves pollen from one flower to the next. The supplied evidence for this species gives no other flower or fruit details. Its taste for wet ground suits a bog garden. Soil moisture matters more than the type of soil.

Grow it in full sun or part shade. It accepts sand, loam, and clay soils. The soil can be mildly acid, neutral, or mildly alkaline. Plants For A Future favours deep, rich soil with much humus. The soil should hold water but let excess water drain. That source says it likely needs moist to wet soil. Sow seed in spring where the plants will grow. The evidence gives no hardiness zone. It gives no set guidance on pests or diseases.

People have used both leaves and seeds as food after cooking. You can grind seeds, mix with water, and cook into porridge. Plants For A Future rates its food value one out of five. The plant can have high levels of oxalic acid. Large servings may cut how much calcium the body takes in. They may cut its uptake of other nutrients too. Cooking lowers the oxalic acid level, but caution is still needed. People with kidney stones, gout, or arthritis should take care. This warning also applies to those with rheumatism or hyperacidity.

Plants For A Future lists past uses as medicine too. People put leaves on burns and drank an infusion for bloat. The source calls the plant astringent and notes tannins in its seeds. These past uses do not prove that treatment is safe or works. The source rates its medicinal value two out of five.