False Buckwheat, Arrowleaf tearthumb
Polygonum sagittatum
Family: Polygonaceae
What it is like
Polygonum sagittatum is a ANNUAL growing to 0.6 m (2ft). It is in flower from July to October, and the seeds ripen from August to October. 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 soil.
Height (m): 0.6
Where it is found
Wet soils. Ditches in Kerry.
N. America - Newfoundland to Northwest Territory, south to Florida. Naturalised in Ireland.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 0
Medicine
Rating: 1
The plant has been used with success in the treatment of nephritic colic, relieving the pains caused by gravel.
Diuretic: Acts on the kidneys, promoting the flow of urine.
Other
Rating:
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: 0-0
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.