Answer: It's really difficult to judge just how often to water a containerized tree. Soil type, weather, and season all contribute. The best thing to do is water thoroughly by saturating the potting soil, then allowing the top 2-3" to dry out before watering thoroughly again. It's normal for the oldest foliage (toward the center of the plant) to brown and drop eventually. As long as the new growth is healthy, there's nothing to worry about. However, if there seems to be an excessive amount of browning, you might closely inspect the affected parts of the plant for insect or disease problems. Fungal diseases can start on the interior of the plant; spider mites can find protected areas in which to feed and breed. Use a magnifying glass to check things out. If you suspect an insect or diseas problem, take a sample of the foliage to your local Cooperative Extension office for positive diagnosis. Helpful folks there can provide control strategies. (OSU Cooperative Extension offices are listed under your County in the white pages of the phone book)
Best wishes with your tree!
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