Rhododendron Giganteum Rhododendron protistum var. giganteum, a variety of an early-flowering tree-sized Grande series rhododendron native to the southeastern Himalayan region. Variety giganteum differs most from the species in that it continues to produce foliage with indumentum into adulthood, while the undersides of the leaves of the species are far less densely hairy. Lovely rose pink flowers with a crimson blotch. Flowers Early (mabye August/September) Will keep growing to the conditions it is in. Rhododendron protistum var. giganteum, a variety of an early-flowering tree-sized Grande series rhododendron native to the southeastern Himalayan region. Variety giganteum differs most from the species in that it continues to produce foliage with indumentum into adulthood, while the undersides of the leaves of the species