Knowledgebase

Azalea Fungus/Mold #926864

Asked March 26, 2026, 7:24 PM EDT

We have 20+ year old Azaleas. They are about 6 ft around. In the last 3-4 years (increasingly) some of them have had whole branches die - first the leave wilts then turn brown and then dies. Currently 3 in front yard (full sun) are more impacted then 2 in shaded back yard under pine trees. Internet search indicates most likely cause - Dieback is caused by Botryosphaeria and Phomopsis fungi, and it shows up as individual branches dying while the rest of the plant looks healthy. The leaves on the affected branch wilt, turn brown, and hang on rather than dropping. If you scrape back the bark on a dying branch, you’ll see red-brown discoloration in the wood underneath. The only solution appears to be cutting out the dieing branches - nothing preventative. Any thoughts. Thanks,

New Castle County Delaware

Expert Response

Hello and thank you for contacting Ask Extension.  

I would recommend that you take samples of the affected plant(s) into our Plant Diagnostic Clinic. This is a free service that can get a positive ID and give you recommendations as to a course of action moving forward.

This is their website:  
https://www.udel.edu/academics/colleges/canr/cooperative-extension/sustainable-production/plant-diagnostic-clinic/

Good Luck and Good Gardening!!

Best regards, 
J.W. Wistermayer 
UD NCC Master Gardener
An Ask Extension Expert Replied March 27, 2026, 9:36 AM EDT

Loading ...