Eastern Redbud die-back
Approx 3 years ago, we purchased an Eastern Redbud from a local Lowes and planted it in a sunny location near a shallow swale in our backyard. It survived the first winter and bloomed the following spring. We had a drought that summer, but kept it watered and it seemed healthy. Following the next winter, it did not bloom or sprout leaves. Instead, in late May, it sprouted new shoots from the trunk about 1-2 inches above the soil line. Shoots grew rapidly throughout summer with leafy green foliage. This spring, same thing. The old shoots died back and it is sprouting anew from the trunk.
We are in northern Illinois and see plenty of redbuds in full bloom in late April/early May, so I know the type can survive here. We bought the tree primarily for it's spring color, but with it dying back each winter, the new shoots do not flower, and it looks kind of stupid having a dead-looking tree in the yard when all the others are leafing out. Is this tree diseased? Not hardy enough? Any advice appreciated.