Honeysuckles (Lonicera spp.) are vines or sprawling shrubs characterised by sweetly scented, bell-shaped flowers. Native to the Northern Hemisphere, honeysuckles are commonly grown as ornamental plants. Honeysuckle plants are susceptible to a number of common diseases and may cause problems for gardeners and local plant life because of their aggressive, invasive growth tendencies.
Common honeysuckle pests include aphids and scale. Aphids are small, soft-bodied insects that feed on foliage, particularly new growth. Aphids rarely cause serious, life-threatening damage, though they reduce a plant's ornamental value. Aphids may be treated with predatory insects, such as ladybirds or lacewings or removed with neem oil or insecticidal soap. Scale insects appear as bumpy, rough patches on the branches or leaves of the plant. They may cause yellowing of foliage and leaf drop. Scale may be removed with predatory insects or simply by pruning away heavily infested parts of the plant. Proper cultural conditions for the plant may prevent an initial infestation.
Honeysuckle is susceptible to diseases such as powdery mildew and canker. Powdery mildew appears as a whitish grey dust over the foliage of the plant. The plant may experience leaf drop, and the overall growth of the vine can be stunted. Powdery mildew is best prevented rather than treated, though it may be treated with a commercial fungicide. Mildew thrives in shady, moist conditions, whereas honeysuckle plants generally prefer bright, sunny areas. Canker is a serious condition that results in sunken spots in the woody branches of the plant, leading to broken and dead limbs. Canker is best prevented by sufficiently watering and pruning the plant.
Some honeysuckle species may quickly become invasive, taking over a garden or escaping outside of the garden and harming local plant habitats. Japanese honeysuckle (Lonicera japonica) is particularly invasive, rapidly growing to lengths of up to 30 feet in even the poorest growing conditions. Small areas of Japanese honeysuckle may be removed by hoeing the soil or simply by moistening the soil and pulling the plant up by hand. Chemical control may be necessary for large plants. Avoid cultivating invasive varieties by growing noninvasive native varieties such as northern bush honeysuckle (Diervilla lonicera) and American fly honeysuckle (Lonicera canadensis).