|R. yakushimanum is named for its native Yakushima Island, Japan. Dense, mounding, evergreen rhododendron, hardy from -5 to -15 degrees F. Leaves are dark green on top, with a thick brown wool on the undersides, from 3 to 5 1/2 inches long. Flowers are borne in trusses of 5 to 10 blooms in mid to late spring.
All rhododendrons love well-drained, acid soil and should be planted high. Partial shade is preferable too, though many tolerate full sun in cooler climates. The evergreen rhododendron thrives in cooler areas of zone 7 and lower, such as the Appalachian Mountains and the Pacific Northwest.