About a year ago, I passed a juniper in my garden that had filled in over the previous growing season. It was a good time to remove the old foliage, so I made a mental note to thin the tree.
A full year later, I still hadn’t thinned the foliage. And then I noticed that some of the branches had turned yellow.
Shimpaku grafted on California juniper –
note the yellow patch on the upper left side of the tree
Similar yellowing showed up on a back branch too.
I knew what the problem was, but took a closer look anyway.
The culprit – juniper scale
Many species of juniper are susceptible to scale when the foliage is overcrowded. Simply thinning healthy trees when they are full can help them resist infestation and stay healthy year after year.
Fortunately the fix is easy. I thinned the tree. This usually makes a dent in the scale population, and I can follow-up with insecticidal soap if needed.
Here’s the tree after thinning.
Shimpaku juniper – 18″ tall
I’ll let the tree recover over summer and look to work on it again after it puts on some new growth, either this winter or sometime next year.
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