Problems With Old Azaleas

I have some very old azaleas. I have noticed a branch that has died. It also happened last year. The leaves turn brown, then the branch dies. I cut the dead branch off but I'm not sure why this is happening. Is this normal or is there something I can do to prevent other branches from dying?

- Sharon S.

Dieback is a disease of azaleas caused by the fungus Phomopsis. Typically, dying branches (stem dieback) begin to appear on an otherwise healthy plant. The leaves die and remain attached to the plant. Usually a single branch or a few branches on an established plant are affected. Scraping away the bark with a knife reveals discolored wood under the bark that appears chocolate brown.

Dieback is difficult to control on azaleas in the landscape. Reduce stress to the plants by planting in partial shade and watering during dry periods. Drought stress and freeze injury may predispose azaleas to infection. Make sure you water the planting deeply once a week during hot, dry summer weather. Keep the bed mulched. It rarely gets cold enough in Louisiana to bother azaleas, particularly in the southern part of the state.

Prune infected branches well below all discolored wood and dispose of dead plant material. Clean pruning tools between cuts with a diluted solution of household bleach (1 part bleach to 9 parts water) or 70% rubbing alcohol. Fungicide sprays containing either thiophanate-methyl or mancozeb can be used after pruning to reduce the chance of additional symptoms.

Dan Gill
Consumer Horticulture Specialist

4/8/2015 1:49:53 AM
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