Polygonum alpinum - Alpine Knotweed

Family:	Polygonaceae
Habit:	Perennial
Height:	1
Width:	1
Synonyms:	P. undulatum
Range:	Europe to E. Asia.

Polygonum alpinum (Alpine Knotweed) is a Perennial which grows to a height of 1m and a width of 1m . It has a hardness rating of 5.
Alpine Knotweed will flower in December to January. The flowers from this plant are hermaphrodite (has both male and female organs) and they are pollinated by Insects

Soil Information

Alpine Knotweed will grow in light (sandy),medium (loamy),hard (clay) soil. It is not necessary for the soil to be well drained.
The soil prefers the following PH / acid levels :
- pH of less than 6, Acidic soils
- pH between 6 and 8, Neutral soils
- pH greater than 8, Basic soils
Alpine Knotweed prefers moist soils

Ideal Planting Locations

Alpine Knotweed can grow in semi or areas with no shade.

Damp meadows, wood margins and mixed grass steppes[74]. Open humus-rich slopes, 2200 - 2700m in Kashmir[145].

Planting places suited to this plant described below.

• Grows within a woodland garden
• Works within dappled Shade
• Grows in a shady edge

Cultivation Details

Succeeds in an ordinary garden soil[1] but prefers a moisture retentive not too fertile soil in sun or part shade[200]. Grows well near water[1]. Repays generous treatment[1]. Plants seem to be immune to the predations of rabbits[233]. Plants can be invasive but they are easily controlled by spading around the clump[200].

Edible Uses*

* See disclaimer
Edible Rating: 2/5
Leaves - raw or cooked[2, 145]. They have an acid flavour and can be used as a sorrel substitute[74]. The chopped leaves and stems have been added to a thick pudding of flour and sugar then eaten[257]. Leaf stems - raw or cooked. An acid flavour, they can be cut into sections and used like rhubarb (Rheum spp)[257]. The juice from the plant has been sweetened and used as a refreshing drink[257]. Seed - raw or cooked. It is rather small and fiddly to utilize.

• Drink - not including plant saps, tea or coffee substitutes.
• Leaves -
• Seed - includes nuts, cereals, peas and beans.
• Stem - this often intergrades into leaves.

Medicinal Uses*

* See disclaimer
Medicinal Rating: 1/5
The whole plant is astringent[74]. The raw roots and stem bases have been chewed as a treatment for coughs and colds[257].

• Astringent - Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
• Pectoral - Relieves respiratory diseases, a remedy for chest diseases.

Propagation

Seed - sow spring in a cold frame. Germination is usually free and easy. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer if they have reached sufficient size. If not, overwinter them in a cold frame and plant them out the following spring after the last expected frosts. Division in spring or autumn. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.

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].

Other Uses

None known

Cultivars

no recorded cultivars

References

Flora of the USSR.
Komarov. V. L.
Author: Komarov. V. L.
Rating:
Publisher : An immense (25 or more large volumes) and not yet completed translation of the Russian flora. Full of information on plant uses and habitats but heavy going for casual readers.
Date of Publication : 1968

The New RHS Dictionary of Gardening. 1992.
Huxley. A.
Author: Huxley. A.
Rating:
Publisher : Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
Date of Publication : 1992

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