It's a grafted tree.

A weeping cherry tree is at its best in spring when the pendulant branches are covered with pink or white flowers. However, all planting locations are at risk of contamination, and the gardener needs to ensure they keep a close eye on the tree throughout the year. Dwarf cherry trees are weeping varieties grown on dwarf, low-growing root stock. The weeping cherry was derived from ornamental cherry trees from Japan. Weeping cherry is an ornamental tree. Weeping cherries are most often top grafted, meaning the scion wood is placed on the sawed-off top of a donor trunk. The tree can be full-size or dwarf. The main trunk is usually like sweet cherry or another ornamental cherry stock, then they graft the weeping cherry to that. Trees planted in flowerbeds are more prone to disease than those in pots. It makes a graceful, elegant specimen tree for front lawns where it … In my experience it's normally not as good as black cherry. Weeping cherry trees do experience a few issues with pests and diseases during the growing season. But btu's are btu's especially if it's in your yard