Horticulture/Lonicera japonica

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.

Description
It is a twining vine able to climb 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, white to yellow, and sweetly scented. The fruit is a globose dark blue berry 5–8 mm diameter containing numerous seeds.

Ecology
Japanese Honeysuckle has become an invasive exotic weed in Argentina, Brazil, Mexico, New Zealand and much of the United States, including Hawaii, as well as a number of Pacific and Caribbean islands. It is classified as a noxious weed in several US states, including Illinois and Virginia. It has done severe damage to eastern American woodlands, often forming vast colonies on forest floors that displace virtually all native ground plants, and climbing into trees and shrubs and severely weakening and even killing them by cutting off sap flow and shading their leaves. Scientists and conservationists have suspected for some time now that it releases allelopathic chemicals into the ground, inhibiting the growth of other plants.

Nonetheless, this species is still sold by American nurseries, often as the cultivar 'Hall's Prolific'. It is an effective groundcover, and does have pleasant, strong-smelling flowers, but the damage it does far outweighs any positive qualities. The only invasive exotics that compete with this plant for total damage done in the eastern United States are ../Kudzu/ and ../Multiflora Rose/.

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; lit. "gold silver flower"). It has antibacterial and anti-inflammatory properties, and is used 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 weak and "cold" digestive system. In Korean, it is called geumeunhwa. The dried leaves are also used in traditional Chinese medicine.