Hydrangea Leaf Tier

Do you grow white flowering Hydrangeas? If your plants are  Annabelle, Incrediball or other form of Hydrangea arborescens you might want to take a close look at the leaves. (Some people have also reported this pest on climbing hydrangeas.) In May there is a sneaky larvae at work that is called a “leaf tier.” This little worm, Olethreutes ferriferana, ties leaves together to form a protective little pocket. Once hidden in this way it proceeds to eat the foliage and developing flower buds.

If you see tied leaves such as the one pictured below, clip them off and throw them in the garbage. You can spray the shrub with spinosad (we have Captain Jack’s Dead Bug Brew) to kill other larvae that may hatch and try to do the same thing. Once inside tied leaves, however, the spinosad won’t be effective, so remove these immediately. Fortunately, the plants will still have time to make new flowers on these stems.

Here is how the leaf tier looks when the leaves are bound together. The larva has knitted the two leaves together so that they don’t open up.

If you look closely at this leaf you’ll see the larva that is responsible. It’s in the center, along the main rib of the leaf, and it has a tiny black head.