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Tuesday - April 22, 2008

From: Mount Vernon, WA
Region: Northwest
Topic: Non-Natives, Shrubs
Title: Problems with azaleas
Answered by: Barbara Medford

QUESTION:

Last summer I planted 10 evergreen Azaleas "Hino Crimson" I sprinkled a little rhody fertilizer in their holes before planting and gave them plenty of water all summer. They are all doing fine except for 3 of them that have reddish leaves and are not blooming this spring, they don't look very healthy.

ANSWER:

Azaleas are considered woodland understory plants. They need acid soil, which is provided by the leaf drop of deciduous trees, especially pines. They can take full sun, but prefer some shade. Since most of your plants are thriving, we can assume that your soil is not the problem.

We found only one azalea native to Washington, the Rhododendron albiflorum (Cascade azalea). However, this really doesn't matter, since you mentioned a cultivar name for your plants. When a plant has been hybridized, you don't know the plants from which it came, and it is hard to make a diagnosis when there are problems. The original species of your "Hino Crimson" are natives of Kurume, Japan. The specific parents are cultivars of Rhododendron obtusum named "Amoenum" and "Hinade-giri". Since none of these plants is native to North America, we are not going to have any information on them in our Native Plant Database. The goal of the Lady Bird Johnson Wildflower Center is to promote, propagate and protect plants native to North America. However, we will try to help you find the problem. Go to this Clemson University Extension website Azalea and Rhododendron Pests and see if any of the symptoms ring a bell. Since the whole plant is doing poorly, and not blooming, we suspect it is a problem with the roots, either root borers or root rot. For more local information and help, contact your Skagit County Extension Service.

 

 

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