How to get rid of leaf curl on hydrangea?

Question from V.J. in Cobourg, Ont.

How do I get rid of leaf curl on hydrangea or prevent the leaf curling pest on Annabelle hydrangeas?

Beckie’s reply:

There is a good discussion of the pest you describe on the Toronto Master Gardeners website (torontomastergardeners.ca).

According to their research, the curling of hydrangea leaves could be caused by one of two insects. “The hydrangea leaftier larva binds two or as many as four leaves together with strands of silk into a cup form and then feeds and rests between them,” according to the website. Pulling apart the leaves will reveal a half-inch-long slender green caterpillar with a black head.

The leafroller also causes similar damage, but rolls only one leaf, then feeds and rests within the rolled leaf.

Both insects cause unsightly damage, but won’t harm the shrubs. When you see the damage in early spring, remove the infested leaves and squash the caterpillars. Clean up the ground below the shrubs, too, because the caterpillars drop to the ground and pupate of the summer and emerge as adult moths the following spring.

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