Some kind of weird mutant radioactive fruit tree in my back yard

The Kousa Dogwood (Cornus kousa or Benthamidia kousa) is a small deciduous tree 8–12 m tall, native to eastern Asia. Like most dogwoods, it has opposite, simple leaves, which are 4–10 cm long. The tree is extremely showy when in bloom, but what appear to be four petaled white flowers are actually bracts spread open below the cluster of inconspicuous yellow-green flowers. The blossoms appear in late spring, weeks after the tree leafs out. The Kousa Dogwood is sometimes also called Chinese Dogwood, Korean Dogwood, or Japanese Dogwood.