|Hello, Two years ago I planted a row of 16 Emerald Arborvitae aprox. 4 ft apart. Suddenly one located in the middle, has begun to bronze. It does not feel brittle or dry. The inside is green but the outside is turning brown. I shook some of the branches over white paper and saw a couple of mites.Not sure if this is an infestation. All of the other trees seem healthy. How should I treat? Thanks!
|Answer from NGA
September 17, 2009
|I don't think a few mites will cause the bronzing on your arborvitae. Mites like dry, dusty places and you can deter them by periodically hosing off your arborvitaes, directing the spray of water in towards the center of the plants. The bronzing is probably a normal reaction to cooler night air. Most will turn in the winter time but then green up again in the spring. I don't think it is anything abnormal but if you'd like you can clip a little of the foliage and take it into a Master Gardener Clinic or into King County Cooperative Extension (Smith Bldg.) in Seattle. They can positively diagnose the problem for you.
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