Answer: Based on your description I am not certain what is happening to your tree. Foliage loss can indicate transplant shock, over or under watering, planting too deeply, a pest or disease problem, or can indicate the tree has died. I would strongly suggest you contact the retailer where you purchased the tree, since it is a new tree and may be under warranty. If they are unable to assist you, you might consult with your local county extension.
In the meantime, make sure you are watering the tree correctly. Your goal in watering is to supplement rain, if needed, so the soil stays evenly moist like a wrung out sponge. It should not be saturated/sopping wet or dried out. To know if you need to water, dig into the soil with your finger. If it is still damp, do not water yet. When you do water, apply it slowly and thoroughly to the root area so it soaks down to the deepest roots. After watering, wait a few hours and then dig down to see how far the water actually went; sometimes it can be surprising. Also, using several inches of organic mulch in a flat layer over the root area (do not allow it to touch the trunk) can help keep the soil cool and moist.
I hope this helps.
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