My front door Daphne was stunningly beautiful and fragrant through the end of March. Now all the leaves are drooping and wrinkled and becoming discolored. We did have a cold snap and a windy couple days the first week of April. No vole nor animal damage is evident. Such a change in just a couple weeks! Since Daphne do not like their roots disturbed, I know not to move it. And I know pruning is tricky. I keep looking at the tips for new growth but it may just be wishful thinking. Is it possible it might bounce back?
A cold snap would only damage a few leaves, at worst.
My first thought is, even though you see no animal damage, voles do chew on the roots or tunnel between them. This is the most common reason for losing daphne shrubs. If all the leaves are wilting and wrinkled, the roots have been damaged and water and nutrients are being replaced by air in the tunnels. You might try digging with your hands around the perimeter of the shrub to see if the soil is disturbed with tunnels. If you find them, then you'll need to exterminate the voles, however, I have no suggestions for how to do that...you'll have to research it.
Second, how old is the shrub? They are not considered long-lived plants.
Hope you find an answer and salvage your shrub...it's one of my very favorites.
Thanks so much for your good advice and suggestion. I did dig around my 3-4 yrs old shrub with my hands and found no tunnels. Just in case, I buried some vole bait around the perimeter. Being on my knees, I got a closer look at some of the leaves and they do appear to have insect disease. I removed the leaves and sprayed. Time will tell.