The family Caprifoliaceae contains an assortment of ornamental plants that are used in the landscape, including Abelia, Kolkwitzia, Weigela, and Lonicera japonica. Abelia, Kolkwitzia, and Weigela are shrubs with showy, fragrant flowers that are used for shrub borders, groupings, or mass plantings. Highway designers, wildlife managers, and landscapers use honeysuckle for a variety of reasons. Managers of wildlife areas plant Lonicera japonica as it provides winter forage for deer. Lonicera is a favorite of gardeners and landscape architects because of its fragrant, beautiful flowers and fast growth. Highway designers use honeysuckle in order to control erosion and stabilize banks. Even though Japanese honeysuckle is a highly desirable, highly utilized ornamental, it has quickly become a problem in the U.S. due to its fast growth rate and ability to displace native plant species. Lonicera japonica has been placed on the Florida Exotic Pest Plant Council’s list of invasive species because of these characteristics.
Lonicera japonica is an evergreen, woody, twining vine. Ovate-shaped leaves are opposite, roughly 1 ½ to 3 inches long with variably pubescent petioles. The younger stems are reddish in color and are fuzzy or slightly pubescent. Hollow, older stems are hollow with brownish bark that peels in long strips. The stems are usually 80-120 feet long.
Lonicera japonica is able to displace native species by outcompeting native plants for light, space, water, and nutrients. Lonicera japonica grows very rapidly, and will send out runners that will root and grow anywhere. In nature, honeysuckle vines will twine around anything growing in close proximity, eventually covering small trees and shrubs. This can lead to the collapse of the trees and shrubs due to the mere weight of vegetation. Dense thickets of vegetation prevent the germination and growth of many native species, eventually preventing the replacement of understory shrubs and trees. Honeysuckle opens the door for many other invasive species to invade, further decreasing the natural diversity of forests or natural areas.
Regular monitoring and rouging of plants can prevent the spread and establishment of Japanese honeysuckle. Programs to educate homeowners on proper plant (honeysuckle) identification will also reduce the spread of this species.
Native alternatives to Japanese honeysuckle for use in home landscaping include trumpet creeper (Campsis radicans), Virginia creeper (Parthenocissus quinquefolia), and trumpet honeysuckle (Lonicera sempervirens). Wild ginger (Asarum canadensis) is an alternative ground cover in shady areas. Good ground cover will also prevent seed emergence and seedling establishment.
Hand-pulling, grubbing with a hoe or a shovel, and removal of trailing vines is practical for small infestations. Remove and destroy all plant material after cutting to prevent rooting and reinfestation. Periodic mowing can slow vegetative spread but may cause resprouting and increase stem density. Aggressive mechanical tillage is also effective, but may not be an option in many areas. However, soil disturbance may stimulate seed germination from the seed bank.
Lonicera japonica has few natural enemies in North America. There are no known biological agents for Japanese honeysuckle. Deer may forage on the plant, but cause limited damage.
Timing of application is critical to effective Japanese honeysuckle control. Many herbicide treatments reduce foliage but leave buds and roots undamaged that can produce new growth. A foliar application of 1.5 to 3% glyphosate or 3 to 5% triclopyr shortly after the first frost appears to be the most effective treatment. Monitor treated plants in case a second herbicide application is necessary.