Hi-

I have two mophead hydrangeas, 2-3 years old. This year the leaves on one of them started curling/cupping like this - upward and inward. The curled ones are pretty rigid and will break if you try to flatten them.

It started as just a couple leaves but now more and more are curling up and I can't figure out why. Leaves that were previously fine curled later, as well as new leaves growing in curled. The soil is moist, not overly so. Doesn't appear to be leaftier (not that I knew what that was before today) or aphids. The other hydrangea is right next to this one in the same bed and it doesn't have any curled leaves at all, so I'm stumped as to what could be affecting this one but not the other. Anything like watering or weather would be the same for both.

Any idea what is going on and how to fix it? I have searched online but haven't been able to find any others with this type of cupping shape, or any other curled leaves that have stayed perfectly green.

Thank you!