Ivy is an extremely versatile plant grown indoors or out. While there are many different ivy varieties distinguishable by shape, size and leaf color, the English ivy is classic. One of the best ways to enjoy the beauty of ivy is to grow it as a topiary tree. Ivy topiaries can be shaped as spheres, cones, animal figures or a creative design of your own. Maintaining ivy topiaries requires careful pruning to achieve the shape you desire. Pruning also controls spread and keeps the tree healthy and attractive.
Pruning for Shape and Height
Pinch and remove foliage and vines that are dead or weak, using your thumb and index finger. If the topiary shape is a sphere or cone, you need to prune deep into the center of the design.
Cut out the lowest new vines and leaves growing on the main stem or trunk with your bonsai pruning shears. This allows you to achieve height for your ivy topiary. Make the cut flush to the junction where the vine meets the trunk.
Cut off growth that is spreading out from the original shape or crowding other foliage. Since the growth rate of ivy differs depending on its variety, your topiary may need to be shaped several times a year. As a rule, prune for shaping purposes when new growth reaches 10 percent of your original ivy topiary diameter.
Pruning to Enhance Light
Look for vines that are creating a canopy that prevents light from entering the main stem. This is a particular problem in ivy topiaries grown in geometric shapes. New vine growth tightens the shape so light is unable to penetrate.
Cut the foliage, being careful not to harm the shape of your ivy topiary.
Trim off growth at the base of the tree if you are unable to see through to the trunk.
Pruning to Control Pests
Examine the leaves of your ivy carefully for mites, scales, mealybugs, whiteflies and aphids. A magnifying glass is helpful in locating these tiny insects on leaves.
Prune off areas that are infected by pests. Be careful not to touch any other foliage when removing infected areas.
Use a pesticide according to directions after disposing of the infected foliage.