Q.azaleas
I have had my azalea for nearly 15 years. The last three years it has failed to flower, and before that I had flowers in abundance each year. Now it looks like it is dying. The leaves are all brown. Can I prune it right back and will it regrow or shall I just dig it up and bin it?
I would inspect the plant carefully for signs of insects. You certainly can treat the plant with Neem Oil, this works as both an insecticide and fungicide.
This could help some possible issue.
It's difficult to say if the plant can recover without knowing the exact cause. Trimming away the dead material and waiting until spring is an option.
Here are some links with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/common-azalea-problems.htm
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/azalea-branches-dying.htm
