Japanese Honeysuckle

The Japanese Honeysuckle (Lonicera japonica; Suikazura 水鬘 or スイカズラ in Japanese) is a species of honeysuckle native to eastern Asia including Japan, Korea, northern and eastern China, and Taiwan, which is a major invasive species in North America. It is a twining vine able to climb up to 10 m high or more in trees, with opposite, simple oval leaves 3–8 cm long and 2–3 cm broad. The flowers are double-tongued, opening white and fading to yellow, and sweetly scented. The fruit is a globose dark blue berry 5–8 mm diameter containing numerous seeds.

Cultivation and uses
The Japanese Honeysuckle flower is of high medicinal value in traditional Chinese medicine, where it is called rěn dōng téng (忍冬藤) or jīn yín huā (金銀花; literally "gold silver flower"). It has antibacterial and anti-inflammatory properties, and is used (often in combination with Forsythia suspensa) to dispel heat and remove toxins, including carbuncles, fevers, influenza and ulcers. It is, however, of cold and yin nature, and should not be taken by anyone with a weak and "cold" digestive system. In Korean, it is called geumeunhwa. The dried leaves are also used in traditional Chinese medicine.

This species is sold by American nurseries, often as the cultivar 'Hall's Prolific'. It is an effective groundcover, and has pleasant, strong-smelling flowers.

Japanese Honeysuckle has become naturalized in Argentina, Brazil, Mexico, New Zealand and much of the United States, including Hawaii, as well as a number of Pacific and Caribbean islands.

Japanese Honeysuckle is classified as a noxious weed in Illinois and Virginia. It can be controlled by cutting or burning the plant to root level and repeating at two-week intervals until nutrient reserves in the roots are depleted. It can also be controlled through annual applications of glyphosate, or through grubbing if high labor and soil destruction are not of concern. Cutting the Honeysuckle to within 5–10 cm of the ground and then applying glyphosate has proved to be doubly effective, provided that the mixture is rather concentrated (20–25%) and is applied immediately after making the cut.