The tiny new leaves emerging on my Limelight hydrangea are curled and distorted. On some, the newest leaves look fine and the second pair are distorted. Obviously a bug or disease is taking hold. Can anyone help me identify the problem?
Did you have any freezing cold weather prior to this problem with the leaves? That is, did the plants break dormancy just before some cold weather hit and now the leaves show some winter damage? Very common in northern half of the country.
Excessive heat from other sources could cause some intraday curling or wilting but it should go away when temps moderate or they receive more shade. Also, some varieties, Nikko Blue for example, sometimes do that when they are young.
Another thing to check... have you recently sprayed any insecticides that could have drifted into these hydrangeas?
You may, of course, have some insects causing problems too (aphids; leaf rollers; spittle bugs too, for example; the nymph sucks the sap and causes the leaf distortion) but you should be able to check the affected and unaffected leaves during the day and at night for these and other pests.