Curlytop Knotweed

Polygonum lapathifolium

Physical Characteristics

Polygonum lapathifolium is a ANNUAL growing to 0.8 m (2ft 7in). See above for USDA hardiness. It is hardy to UK zone 5. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.

Distribution

Temperate regions of the northern hemisphere, including Britain. S. Africa.

Habitats

Bog Garden;

Edible Uses

Edible Parts: Leaves Seed Edible Uses: Young leaves - raw or cooked[105, 177]. Seed - raw or cooked. It is rather small and fiddly to utilize.

Medicinal Uses

Antiseptic Astringent Febrifuge Stomachic The whole plant is antiseptic and astringent[178]. An infusion has been used in the treatment of stomach complaints and fevers[257]. The plant produces a soft white mass, a froth like that of soap. It is applied externally to burns[272].

Known Hazards

Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. 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].