Rhododendron yakushimanum ( Ken Janeck Yakushima Rhododendron )
R. yakushimanum is named for its native Yakushima Island , Japan . obtuse , mounding , evergreen rhododendron , hardy from -5 to -15 degree F. Leaves are dark green on top , with a thick chocolate-brown wool on the undersides , from 3 to 5 1/2 column inch long . Flowers are borne in trusses of 5 to 10 blooms in mid to late bound . All rhododendrons do it well - drained , acid soil and should be planted high ....