UACES Facebook Azalea Leaf Gall

Azalea Leaf Gall

(May 2007)

QuestionI have an azalea that has the problem of waxy leaves that you wrote about earlier.  The leaves get thick and waxy and malformed.  It had no blooms this year.  I pruned it severely and used 13-13-13 fertilizer.  New shoots are coming out, but some of the leaves appear to be getting thick and waxy. I am pulling them off immediately.  Can I expect blooms next year or is this plant a goner?


AnswerAzalea leaf gall is a disease that usually looks worse than it actually is.  The disease starts out with a few leaves getting thick and waxy and usually a bright green in color.  Over time they turn whitish with disease spores accumulating.  The key is to prune them off as soon as you see the problem to prevent disease spores from forming.  The spores don’t affect the plants this season, but come back to haunt the plants the following spring.  Now that the temperatures are warming up, the disease should actually stop.  This is a disease that is active during cool, wet weather.  It should not have kept your azaleas from blooming.  Fertilize once more in mid June and keep the plants watered, and hopefully they will set plenty of flower buds.  We have had two seasons where azaleas did not bloom to their normal potential—the winter of 2005 was warm and dry which caused some flowers to abort, and this year the late freeze damaged many azalea blooms.

(May 2006)

QuestionMy azaleas weren’t their best this spring, but I wrote that off to the weird winter. Now I have numerous leaves that look like thick growths are taking over. Is this what caused the flowers to be less showy and is it going to kill my plant? Is there a spray I should be using?


AnswerAzalea leaf gall is beginning to appear after our recent bout with cool, wet weather. This fungal disease is short-lived and looks much worse than it actually is. It starts out looking like someone poured candle wax on the leaves. They get quite thick and fleshy. If left alone, they will turn from light green to white or gray. No sprays are needed, nor will help. Simply snap off the damaged leaves and dispose of them. Once the weather warms up the disease will stop. It really doesn’t hurt an established plant, and is not responsible for less blooms this spring—you were right the first time—our weird winter weather (dry and warm) did cause some flowers to be aborted.


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