A woody vine, clematis comprises approximately 250 species. Some varieties grow as deciduous specimens and others as evergreens. Once established, the clematis has the ability to thrive with few pests. One plant has the capability of producing up to 100 blossoms in a season. Some varieties attain a height of up to 20 feet, but others only grow 2 to 4 feet.
The clematis borer’s Alcathoe caudata larvae burrows into the plant’s root system. One generation of the insects occurs per year. The larvae spend the winter months deep in the plant’s root system. The larva’s feeding causes the stems of the clematis to die. In the spring, the larva emerges as an adult moth that measures slightly over 1 inch in width and sports a wasplike body. The black insect sports translucent wings. The females usually appears slightly larger than the male. Consider spraying beneficial nematodes, such as Steinernema carpocapsae, around the base of the clematis plant to control the larvae. Insecticidal sprays that contain chlorpyrifos will kill emerging adult moths.
Two varieties of plant bugs occur on the clematis, the four-lined plant bug Poecilocapsus lineatus and the tarnished plant bug Lygus lineolaris. The pests suck attach their powerful mouth to the plants stems and leaves. The leaves often have sunken areas which eventually become holes. Once attached they suck the plant’s sap. The four lined plant bug has alternate colored stripes in shades of green, yellow and black. The tarnished plant bug has a brownish body with yellowish markings on its back. Control the insects by spraying the plant with horticultural oil or insecticidal soap in the spring months.
Aphids often congregate along the clematis vine’s new growth and leaves. They use their piercing mouth parts to suck the nutrients from the plant. Consider hosing the insects off using a strong burst of water every few days. Snails and slugs can also cause damage to the clematis vine’s foliage. Slugs can also feed on the vine’s bark. Handpick the pests during the dark hours using a flashlight to locate them. Consider using slug and snail baits for control. Earwigs can cause damage to the plant’s blooms or foliage by feeding on them. Use an insecticidal spray to control the earwigs. Follow the directions on the label for application instructions.
Maintain a healthy clematis vine to help reduce the damage it sustains from insects. Plant the vine in a location that receives at least six hours of sunlight per day. The clematis enjoys a planting location with well-draining soil. Keep the vine moist but not overly wet. Apply approximately 1 inch of water per week if the area does not receive adequate rainfall. Apply a layer of mulch around the base of the vine to provide it with winter protection. Remove any damaged or diseases canes and dispose of them.