How to Identify and Remove Japanese Honeysuckle

Japanese honeysuckle is an extremely vigorous perennial vine that is deciduous in northern climates but often evergreen in warmer areas. Japanese honeysuckle is native to eastern Asia including China, Japan, and Korea and was introduced to the United States in 1806 as a plant for erosion control, as well as an ornamental. Its fragrant flowers and long bloom period tempted many gardeners to plant it only to find out that this is a highly invasive species that has escaped cultivation and crowds out native species. While Japanese honeysuckle is still available from nurseries, home gardeners are strongly advised not to plant it, and remove any Japanese honeysuckle from their landscape. The berries of Japanese honeysuckle are toxic to humans.

Common Names	Japanese honeysuckle, Chinese honeysuckle, golden-and-silver honeysuckle, Hall's honeysuckle
Botanical Name	Lonicera japonica
Plant Type	Perennial, vine
Mature Size	15-50 ft. long, 3-6 ft. wide
Soil Type	Well-drained
Bloom Time	Spring, summer, fall
Flower Color	White, yellow
Hardiness Zones	5-8 (USDA)
Native Areas	Asia
Toxicity	Toxic to humans

Japanese Honeysuckle Invasiveness

Warning

Japanese Honeysuckle was often planted because it does well in shady locations and dry soils. Today, it is considered an invasive species in many states. It is listed as an invasive plant up the East Coast to the southern parts of New England. In parts of the country where its foliage is evergreen, and thereby more vigorous, it is especially invasive.

Japanese honeysuckle endangers trees by twining around tree trunks and girdling them. It climbs into the tree canopies, eventually crushing the tree with its weight. Japanese honeysuckle also harms shrubs and other vegetation by forming dense arbors and mats on the ground, depriving other plants of light and nutrients and crushing them with its weight. On the ground, the vines grow 6 to 10 feet long. When growing up a tree, the vine grows considerably longer, reaching up to 50 feet. Under ideal conditions, the vine can grow up to 30 feet annually. Japanese honeysuckle spreads through its vines and seeds when birds and other wildlife eat the berries.

It is illegal to plant Japanese Honeysuckle in several states, including:

• Connecticut
• Illinois
• Massachusetts
• New Hampshire
• Vermont

Even if it's not illegal to sell in other areas, it's on the Noxious Weeds list in 46 states and remains a problematic plant that can harm the ecosystem.

What Does Japanese Honeysuckle Look Like?

Japanese honeysuckle is deciduous in colder climates, and evergreen in warmer climate zones. It twines around trees and inanimate objects, a characteristic that distinguishes it from native honeysuckle species with tendrils, adhesive disks, or aerial roots.

The stems of the young vines are green with fine hairs; as the plant gets older, the vines become woody with a brown, irregularly peeling bark. The stems are brittle and hollow.

The long, egg-shaped, and hairy leaves of the Japanese honeysuckle are opposite, two per node. Between April and July, the vine has fragrant white flowers with a purple or pink tinge. The flowers attract butterflies and hummingbirds. Japanese honeysuckle has a long bloom period from late spring into fall, which is one of the reasons it was valued as an attractive ornamental.

Between September and November, the flowers turn into black, shiny berries.

Japanese honeysuckle vine is not the only invasive honeysuckle species, there are also invasive bush honeysuckles native to Asia and southern Russia, including Amur honeysuckle (Lonicera maackii), Bell’s honeysuckle (L. x bella), Morrow’s honeysuckle (L. morrowii), and Tatarian honeysuckle (L. tatarica).

How to Get Rid of Japanese Honeysuckle

Removal of Japanese honeysuckle depends on the severity of the infestation.

If you only have only a few small vines growing in your yard, you can pull them by hand. Do this before they set fruit in the fall to prevent the seeds from being dispersed by wildlife.

You can also cut the vines down to ground level any time between the spring and the fall although the late summer is best. Immediately brush the cut stumps with liquid undiluted broad-spectrum herbicides (glyphosate or triclopyr). Do not just cut the vines without applying a herbicide afterwards, as this will encourage more vigorous growth and aggravate your problem. The cut stump method is safer for surrounding plants and more targeted than spraying the vine's foliage with diluted herbicide solution.

Large areas of honeysuckle should be mowed down as close to the ground as possible. When new growth begins to sprout, spray it with a diluted solution of glyphosate as directed on the product label. Be sure to wear protective clothing including gloves and goggles.

No matter the size of the infestation and how you control it, it is important that you keep an eye on the area to re-treat or remove any newly sprouting vines promptly.

From: thespruce