Failure to thrive Azalea type 1 - Ask Extension
Well established Azaleas (3 in total) in a raised bed facing west and receive 4-5 hrs of sunlight each day. Shrubs are in the same location for 8+ ye...
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Failure to thrive Azalea type 1 #855408
Asked November 16, 2023, 4:43 PM EST
Well established Azaleas (3 in total) in a raised bed facing west and receive 4-5 hrs of sunlight each day. Shrubs are in the same location for 8+ years. Leaves show discoloration, spots, etc. for the past year or two. I have not provided any supplements, fertilizers, water, etc to the area. Would appreciate any suggestions on how to help the shrubs thrive again.
Frederick County Maryland
Expert Response
It is not easy in late fall to assess plant problems as most plants have tired, spotty and discolored leaves in the fall.
We think that the shrubs are stressed and struggling a bit from both abiotic (environment and care) and pest issues.
The abiotic factors may be too much sun for their general liking, paired with very dry conditions we had this year. Large parts of Maryland have been either 'severely dry" or in drought conditions for many weeks this season so some supplemental watering was needed to keep most plants thriving. Make sure too that your mulch is not deeper than about 3 inches, and remove any more than that. (Here is our tree and shrub watering information:
https://extension.umd.edu/resource/watering-trees-and-shrubs#:~:text=How%20to%20water%20trees%20and,less%20tolerance%20for%20dry%20conditions.)
You can water the plants now and can continue (if we don't get at least an inch of rain a week), right up until the ground freezes for winter.
It does look like you have some signs of lace bug damage on some of the leaves, which is common, particularly when azaleas are hot, sunny areas (late afternoon sun is most taxing).
During the growing season flip the leaf to look at the underside and see if you see their black fecal spots.
Here is our page on Lace Bugs:
https://extension.umd.edu/resource/lace-bugs-trees-and-shrubs
In landscapes where pesticide use is minimal and where there is good biodiversity (multiple plant types that support a diversity of good insects and other life) they are taken care of naturally by beneficial predator insects such as
tiny parasitic wasps, predatory assassin bugs, lacewing larvae, lady beetles, jumping spiders, pirate bugs, and mites.
Christine
We think that the shrubs are stressed and struggling a bit from both abiotic (environment and care) and pest issues.
The abiotic factors may be too much sun for their general liking, paired with very dry conditions we had this year. Large parts of Maryland have been either 'severely dry" or in drought conditions for many weeks this season so some supplemental watering was needed to keep most plants thriving. Make sure too that your mulch is not deeper than about 3 inches, and remove any more than that. (Here is our tree and shrub watering information:
https://extension.umd.edu/resource/watering-trees-and-shrubs#:~:text=How%20to%20water%20trees%20and,less%20tolerance%20for%20dry%20conditions.)
You can water the plants now and can continue (if we don't get at least an inch of rain a week), right up until the ground freezes for winter.
It does look like you have some signs of lace bug damage on some of the leaves, which is common, particularly when azaleas are hot, sunny areas (late afternoon sun is most taxing).
During the growing season flip the leaf to look at the underside and see if you see their black fecal spots.
Here is our page on Lace Bugs:
https://extension.umd.edu/resource/lace-bugs-trees-and-shrubs
In landscapes where pesticide use is minimal and where there is good biodiversity (multiple plant types that support a diversity of good insects and other life) they are taken care of naturally by beneficial predator insects such as
tiny parasitic wasps, predatory assassin bugs, lacewing larvae, lady beetles, jumping spiders, pirate bugs, and mites.
Christine
Thank you for your help and advice
Mark
You are welcome. We're happy to help.
