Got holes in your leaves? Don't reach for the insecticide that is guaranteed to kill a wide spectrum of different insects or the Bacillus thuringiensis (just kills caterpillars) until you know what the culprit is, or you may just destroy a beneficial insect instead!

Leaf cutter damage to peony leaf

The leaves of some of the plants, in my herbaceous borders frequently develop a tessellated appearance around the edges due to the nibbling of leaf-cutter bees (megachildae), and when other gardeners come to visit I am surprised at how few people recognize the very distinctive pattern on the leaf edges.   Roses and peonies are the most frequently visited, and quite often only a particular stem of leaves on a plant appeals to them. In a garden that I tend and which has a collection of roses only one plant is ever used and nearly all the leaves on that plant have been much chewed while the others are untouched.

If bees visit flowers for nectar and pollen why on earth are they chewing on leaves? Well this particular species of bee lays its eggs in holes in wood, often using old beetle holes or bug hotels, then fills each hole with pollen and resin to provide food for the larvae and finally seals the hole with a piece of leaf or flower petal.

 

Generally speaking leaf-cutters do little damage to the plants that they harvest from so no action needs to be taken to control them. However, this spring I installed a pollinator-friendly garden which included a very small 'Rising Sun' redbud tree. I don't know if it was the citrus-colored leaves that appealed, but beginning in July every new leaf was quite severely damaged and our bee house was very artistically decorated, implying that my pollinator garden was a great success for at least some species.

The pleasure that I get observing the many different species of bees in the garden far outweighs any damage that they do, so no sprays will be used, and if the damage becomes severe I can put a fine mesh net over my little tree until it becomes established.