Hi Jana, this is Kimberly from landscape-solutions-for-you. Thank you for asking a question on your cherry tree. Clay and sandy soil are a good mixture for your tree. It sounds like you have been watering the tree. When leaves turn yellow it is a sign of lack of water or too much watering. Take a small sharp knife and scratch the surface of the trunk. If it is green, the tree is still alive. If it is brown, the tree is in shock. There are a few reasons the tree could be in shock.
1. Soil lacking nutrients
2. Grass clippings up against trunk
3. Light requirement not right
4. Watering
5. Too much fertilizer being given
6. Tree planted too deep or not deep enough
I would recommend to look at each of these above. If you cherry tree has green on the trunk the leaves may be turning yellow due to one or more factors from above. You might want to consider adjusting the fertilizer, watering, or try mulch or pine straw instead of grass clippings. Also check and see if your tree is under warranty. One of thing you might do, is take a small some leaves and possibly a small branch to a local nursery and have them look at it.
I hope some of these suggestions can get you moving in the right direction. Let us know how you make out. When trees or shrubs go into shock or are dying, they go through the same steps that a doctor would take in trying to find out what is wrong with his or her patient. Good luck to you and have a great day. Feel free anytime to ask a question here at landscape solutions for you.
Kimberly