Honeysuckle - Lonicera japonica
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The Japanese Honeysuckle (Lonicera japonica; 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.
The Japanese Honeysuckle flower is of high medicinal value in traditional Chinese medicine, where it is called r?n d?ng tén or j?n yín; 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.
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 (in climates suitable for it) 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.
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.
Website, video, and graphics by Rob Nelson
For more information on this plant or management please contact US Army Corp of Engineers