Japanese Knotweed

(Fallopia japonica)

Other Names:
(syn. Polygonum cuspidatum, Reynoutria japonica)


Polygonaceae – Buckwheat family

Growth Type:
An invasive species, Japanese Knotweed is a tall shrub-like weed that grows in large colonies.

Can grow to 9 - 12 feet tall, although usually found much smaller

The leaves are spade shaped, and can be rather large. They are relatively flat at the base, and pointed at the tip, just like the end of a spade.

The stems are hollow with enlarged nodes, just like bamboo. During the winter, stands are easily identified as they look like stands of dried bamboo.


Flower Season:
Late Summer and Early Autumn

Flower Appearance:
The flowers are small, cream or white, produced in erect racemes 6–15 cm long


Miscellaneous characteristics:
An invasive species native to eastern Asia in Japan, China and Korea, which has become widespread throughout the US.

Disturbed soils, yards, old homesteads, roadsides

Parts Used:
Young Shoots as food. Roots for medicinal purposes.

Wild Food Uses:
The young shoots can be eaten raw, or cooked. they have a sour almost rhubarb-like taste. I have heard they can be used in pies, but I have not tried this myself. Some caution should be taken when consuming this plant, as it contains oxalic acid. There is a possibility that in very large quantities oxalic acid may aggravate conditions such as rheumatism, arthritis, gout, kidney stones or hyperacidity.

The following text is meant for informational purposes only. It is not meant to diagnose or treat any illness or injury. Always consult with a physician or other qualified medical care provider concerning the diagnosis and treatment of any illness or injury.

Medicinal Uses:
Japanese knotweed is a concentrated source of emodin, which has been used to regulate bowel function and motility. The roots of Japanese knotweed are used in traditional Chinese and Japanese herbal medicines as a natural laxative. The effective dosage has been 20 to 50 mg per day. The root has also been used in Korea to maintain oral health. It has been shown to reduce the viability of Streptococcus mutans and Streptococcus sobrinus. (Medicinal usage information gathered from Wikipedia., as I have not used this plant medicinally)

Medicinal Actions:
Antiviral, Aperient, Cathartic, Laxative