Box Tree Caterpillar
Pest · Commonly affects: Box hedging, Box topiary, Buxus sempervirens, Dwarf box, Box edging, Container-grown box
Box tree caterpillar is a serious pest of box, or Buxus, hedging and topiary in many parts of the UK. Its caterpillars can remove leaves quickly and repeatedly, leaving plants thin and bare. Early attention gives box the best chance to recover, particularly where hedges are closely clipped and difficult to inspect.
How to identify it
Look closely within box foliage for green caterpillars with black heads, black stripes and pale hairs, growing to about 40 mm. Fine webbing, greenish-black droppings and chewed leaves are often seen before the caterpillars themselves. Small caterpillars hide deep in the plant, while larger ones may be visible on outer shoots. Pale yellow eggs can occur on leaf undersides. Adult moths are usually white with a brown border, although brown forms also occur.
Damage
Caterpillars eat box leaves and may also strip the green bark from young stems. A heavy infestation can defoliate a hedge or topiary rapidly, leaving webbing and bare twigs. Repeated attacks weaken plants, reduce their ability to recover after clipping and can leave formal shapes patchy for a long time. Dense, sheltered box is most easily overlooked.
Prevention
Inspect box plants regularly from spring to autumn, parting dense foliage to look for webbing, droppings and small caterpillars. Check new box plants before purchase and before planting near established hedges. Keep clipped material and fallen leaves cleared from around plants, and avoid moving infested prunings through the garden. Pheromone traps can help indicate moth activity. Encourage insect-eating birds by maintaining a varied, wildlife-friendly garden, while protecting nesting birds during any work.
How to manage it
Hand-pick caterpillars and remove webbing as soon as it is found, checking deep inside the plant as well as outer growth. Prune out badly affected shoots only where this will not leave excessive bare wood, then dispose of removed material in household waste. A strong water spray can dislodge small caterpillars from accessible plants. Biological nematodes may help where conditions are suitable. Reinspect weekly, as eggs can hatch over an extended period.
Box Tree Caterpillar: frequently asked questions
How do I identify box tree caterpillar?
Look closely within box foliage for green caterpillars with black heads, black stripes and pale hairs, growing to about 40 mm.
How do I prevent box tree caterpillar?
Inspect box plants regularly from spring to autumn, parting dense foliage to look for webbing, droppings and small caterpillars.
How do I get rid of box tree caterpillar?
Hand-pick caterpillars and remove webbing as soon as it is found, checking deep inside the plant as well as outer growth.
General guidance for UK home gardens and allotments, focused on prevention and non-chemical control. For a confirmed diagnosis, the RHS or a local garden centre can help. Page updated 19 Sep 2026.