Hydrangeas are hardy shrubs that are rarely troubled by insects. Despite their sturdiness and overall resistance to disease and infestation, however, hydrangeas may sometimes be attacked by common plant-eating insects.
Root maggots are the larvae of maggot flies and among the most common root-attacking insects. Most of the several varieties prefer the roots of a specific plant. Hydrangeas are susceptible to all types of root maggots if the conditions are right.
Stem and Foliage-Attacking Insects
Aphids and spider mites commonly attack leaves and stems and may attach themselves to hydrangeas. They eat away at leaves, leaving mottled, discoloured foliage in their wake. They are normally easily handled with a solution of water and dishwashing liquid sprayed on the shrubs.
Asian lady beetles, leafrollers and several other varieties of bugs may attack or even lay eggs within the flowers or buds of hydrangea plants. These pests are extremely rare in hydrangeas and may usually be eliminated with a pesticide treatment or the introduction of predatory insects.