Common Name: Mile a minute weed

General Information

Persicaria perfoliata is an annual to perennial plant with trailing stems growing 80 - 200cm long, sometimes to 700cm or more[, ]. The stems have recurved barbs, which allow it to clamber over other plants to reach the light[].
The plant is sometimes gathered from the wild for local use as a food and medicine. It has been cultivated as a leaf vegetable in south Benin[] and has sometimes been grown as an ornamental.
Persicaria perfoliata is a fast growing, spiny, herbaceous vine. Like many other members of the genus, it can be an aggressive and/or invasive weed. It has invaded a wide range of habitats in the USA, being found on stream banks, moist thickets, roadsides, nurseries, wood-piles, clearings and ditches, thriving where forests are clear-cut. The plant scrambles over shrubs and other vegetation, and blocks their foliage from available light, thus reducing their ability to photosynthesize. If left unchecked, the shaded plants are killed, and large infestations eventually reduce native plant species in natural areas. In addition, the leaves, petioles, and stems of Persicaria perfoliata contain prickles, causing the movement of wildlife, and human activities to be impacted in infested areas. In its native China the plant has rarely been recorded as an important noxious weed in either agriculture or the environment[, ]. The plant is a threat to ecosystems as it has the ability to outgrow the native species[].

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[].

Botanical References

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Range

E. Asia - Russian Far East, China, Japan, Korea, Nepal, Bhutan, Bangladesh, NE India, Thailand, Vietnam, Malaysia, Indonesia, Philippines, New Guinea

Habitat

Wet thickets and by rivers in lowland all over Japan[]. Open and disturbed areas, along the edges of woods, wetlands, stream banks and roadsides. It also occurs in environments that are extremely wet with poor soil structure[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Habit	Annual/Perennial
Height	1.80 m
Pollinators	Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

A plant of the warm temperate to tropical zones.
Succeeds in an ordinary garden soil[] but prefers a moisture retentive not too fertile soil in sun or part shade[]. Repays generous treatment[]. It can survive in areas with relatively low soil moisture, but demonstrates a preference for high soil moisture413]. Available light and soil moisture are both integral to the successful colonization of this species. It will tolerate shade for a part of the day but needs a good percentage (63-100%) of the available light. It can reach areas of higher light intensity by attaching to and climbing over other plants with its recurved barbs[].
Plants seem to be immune to the predations of rabbits[].

Edible Uses

Tender young leaves and shoots - raw as a salad or cooked[]. An acid flavour[]. Used as a vegetable[]. Cooked with other greens and eaten as a side dish with rice[].

Seed - raw or cooked. It is rather small and fiddly to utilize. The ripe fruits (seeds) are eaten fresh, especially by children[].

Medicinal

The whole plant is depurative, diuretic and febrifuge. It is also used to stimulate blood circulation[]. A decoction is used in the treatment of dysentery, enteritis, boils and abscesses, poisonous snake bites, haematuria, cloudy urine and traumatic injuries[].

The juice of the leaves is used in the treatment of backaches[].

Other Uses

None known

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.