Euscaphis japonica (Staphylea japonica) is a mid-size ornamental tree that was introduced by the late horticultural legend J.C. Raulston who discovered the Korean sweetheart tree in 1985 on the Korean Peninsula while participating in a U.S. National Arboretum collection expedition. The Sweetheart tree is very showy in fruit, though the glossy, dark, evergreen foliage contrasted by the pale bark make it an attractive tree for year-round interest. Zones: 6a to 8b. | Plant Delights Nursery, Inc.