I bought a plum tree 2 years ago from Wal mart. It's about 8 feet tall. This spring it didn't produce many leaves. Most of the branches are bare with a few leaves here and there. They haven't died off, just didn't produce much, but it is growing new stems!
Why Does My Plum Tree Have Hardly Any Leaves?
Certified GKH Gardening Expert
It sounds like it may have a fungus. Treat the tree with a fungicide and this will kill the fungus. It should try to grow its leaves once the issue is resolved, but may not have time before fall comes. If this is the case, it will need extra care and protection to make it through the winter as its energy reserves will be low.