Where are you located? Knowing it is in the United States is far too broad. Knowing your USDA zone would help a little, but knowing at least the state would help you get advice that is directed to what plants in your area have, need or don't need, as well as what is or ins't suitable for your area. Knowing the section of the state, as in coastal, mountain, etc., etc. would help even more. As it is, only the most general advice can be made.

Probably, the tree is still adjusting and will be fine. However, where did you buy it from, a good nursery or a big box store? Where did you plant it, full sun, full shade or in between? I assume you have been watering it as advised. What has your weather been like - cooler than normal, normal, very cool nights, hot days, etc., etc?

I'm in Denver, CO - zone 5 I guess. Tree was bought from a tree farm...the most reputable one in the area. It's in a part sun area where it should be successful. I had another Newport Plum tree there before that was doing well but it was real small and I wanted something larger that could provide more shade for the area. Weather has been warmer than normal the past two weeks. I watered it well when it was planted and we have had a couple good rain showers since it went into the ground.

Then it should be OK. Give it more time. As long as it has green cambium, it should grow eventually.

Give it the equivalent of an inch of rain per week, as a slow watering so the water gets to the bottom of the root ball. stick a finger down into the soil before you water - if it's still damp in the top couple of inches, wait and check again the next day.

If you haven't mulched the tree, do so - no more than 4" deep, no mulch in the 2-4 inches next to the trunk, and as wide as possible, at least out to the drip line. This will moderate soil temperature and moisture, and will also keep grass roots from competing AND keep lawn mowers and weed whackers away from the trunk! Any mulch will do, although I am partial to double-ground, aged hard wood mulch. DON'T use landscape cloth under it - it doesn't really work, roots grow up into it, and it's a royal pain to remove when you finally get fed up with it. If you have grass in the to-be-mulched area, you can smother it by spreading flattened cardboard or 4-6 sheets of black-ink newspaper down first. If you keep the edges covered so it doesn't wick moisture away, the paper will break down and disappear into the soil inside a year.