Leaf-cutter bee
Neat semicircular or oval pieces cut cleanly from the edge of a leaf, most often on roses, wisteria and lilac. Solitary bees remove them to line their nest cells. The cuts are so regular that they are unmistakable once seen — no chewing insect leaves an edge that smooth — and the damage is cosmetic: a plant can lose a good many leaf margins without any measurable effect on its growth.
Caused by: Megachile spp. · also called leafcutter bee, semicircular holes in leaves
What brings it on
Warm weather from late spring to midsummer, on smooth-leaved shrubs near a nest site — a bee hotel, a hollow stem, soft mortar or an old wall. The cuts appear over a few days and then stop, because a single female is provisioning a small number of cells.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Leaf-cutter bees
Checked 2026-08-13
Preventing it
Ordered by how much difference each measure actually makes, not by how often it is repeated.
- None worth taking. Netting a rose to keep bees off it costs more than the damage does, and the insect is a pollinator worth having in the garden.
source
GrowingHQ editorial positionhigh confidence
A judgement about proportion rather than a horticultural fact, so recorded as editorial.
- GrowingHQ editorial synthesis — GrowingHQ
Checked 2026-08-13
Dealing with it once it is there
- Nothing. The plant is not meaningfully harmed and the bees are beneficial — several British leaf-cutter species are declining, and insecticides applied to a plant in flower reach far more than the intended target. If the cut leaves bother you, remove the worst of them; the bee will have finished within a week or two.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Leaf-cutter bees — control
Checked 2026-08-13
On sprays and treatments
GrowingHQ does not tell anyone what to apply, at what rate, or how often. Pesticide approvals differ by country, change without notice, and the product label is legally binding — it is also the document you are holding. What is described here is cultural and physical control, which is what a home grower can act on without a label in front of them.
Plant-specific guides
Where this is one of several causes that look alike on a particular plant, GrowingHQ publishes the differential rather than the general answer.