Red Leg, Spotted ladysthumb
Polygonum persicaria
Family: Polygonaceae
What it is like
Polygonum persicaria is a ANNUAL growing to 0.6 m (2ft). See above for USDA hardiness. It is hardy to UK zone 5. It is in flower from June to October, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs). The plant is self-fertile. 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 soil.
Height (m): 0.6
Where it is found
Damp shady places. A common weed of cultivated land, avoiding shade.
Temperate regions of the northern hemisphere, including Britain.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 1
Leaves and young shoots - raw or cooked. They contain about 1.9% fat, 5.4% pectin, 3.2% sugars, 27.6% cellulose, 1% tannin. Seed - raw or cooked. It is rather small and fiddly to utilize.
Seed: includes nuts, cereals, peas and beans.
Medicine
Rating: 2
The leaves are astringent, diuretic, rubefacient and vermifuge. An infusion has been used as a treatment for gravel and stomach pains. A decoction of the plant, mixed with flour, has been used as a poultice to help relieve pain. A decoction of the plant has been used as a foot and leg soak in the treatment of rheumatism. The crushed leaves have been rubbed on poison ivy rash.
Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
Diuretic: Acts on the kidneys, promoting the flow of urine.
Lithontripic: Removes stones from the kidney, bladder etc.
Poultice: A moist, usually warm or hot, mass of plant material applied to the skin in the treatment of burns etc.
Rubefacient: A counter-irritant and external stimulant, it produces inflammation and redness of the skin.
Vermifuge: Expels and kills internal parasites.
Other
Rating: 1
A yellow dye is obtained from the plant when alum is used as a mordant.
Dye: Plants that provide dyes.
How it is grown
Succeeds in an ordinary garden soil but prefers a moisture retentive not too fertile soil in sun or part shade. Repays generous treatment. Plants seem to be immune to the predations of rabbits.
Propagating it: Seed - sow spring in situ.
Best place to grow: Cultivated Beds;
Habit: Annual
Hardiness: 4-8
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: Moist
Things to keep in mind
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.