Leaf curl on Rhododendrons is most frequently seen when the plants are under stress from drought, stem injury or cold temperatures. Sometimes one or more of these are contributing factors because if the rhodys went into the winter season dry from summer drought they are then more likely to be further stressed by cold winters. If heavy snows break branches, so that they can no longer take water up to the leaves, this too causes foliage to curl and die.
What’s to be done now? In the spring we all play a waiting game. If the leaves of your plants haven’t recovered in the next week or two they are unlikely to do so. You can take one of two actions: 1. Clip off the wilted foliage just above the last two leaves. This will prompt new growth from the area where you’ve left two leaves. 2. Wait and see how the plant recovers in late-May. Some Rhododendrons drop those curled and soon to be dead leaves but will put out new foliage from those stems in late May. Other plants will continue to die back and you’ll see in early June that these branches are indeed dead, at which point you can cut them off.
Fertilizer won’t fix the problem so don’t go there. But a light application (an inch thick) of composted manure around the base of the plants is never a bad idea, so by all means put this down and then wait and see what happens.
should I still water the plant or feed until June?