This is Rhododendron arboreum, also known as tree rhododendron, burans, and gurans. This brilliant explosion of bursting red flowers is a showstopper and the national plant of Nepal. The very young and tender leaves can be cooked and eaten as a vegetable, and the flowers can be eaten raw or cooked. It is common to pickle the flowers in chili and salt. The wood is very useful for fuel, coal, and building a wide variety of items. Bees love these flowers and the Rhododendron honey is very tasty. Rhododendrons in general are larval host plants for the Gray Comma, Appalachian Tiger Swallowtail butterflies, and the Elegant sphinx, 10 spotted Rhododendron, Tetracis jubararia, and Rhododendron Borer moths. USDA Hardiness Zones 6 to 9.