Leaf curl often happens when a fungus is present. It could be azalea gall (to which rhododendrons are also susceptible). Gall is a fungus spread by rain. It normally occurs during cool, wet weather. If this is gall, you can pick it off by hand; fungicides can be applied. See your local organic nursery supply store.
Leaf curl often happens when a fungus is present. It could be azalea gall (to which rhododendrons are also susceptible). Gall is a fungus spread by rain. It normally occurs during cool, wet weather. If this is gall, you can pick it off by hand; fungicides can be applied. See your local organic nursery supply store.