Rhododendron subg. Hymenanthes is a subgenus of the genus Rhododendron, with a widespread distribution in the temperate Northern Hemisphere. The species are evergreen shrubs and small to medium-sized trees (up to 20 m tall), with medium-sized to large leaves (very large, over 40 cm long, in a few species). The flowers are large, produced in terminal trusses of 5-40 together.
The subgenus includes one section, Rhododendron sect. Ponticum, divided into 24 subsections and about 140 species. In 2005 the subgenus was expanded by adding section Pentanthera.
Section Ponticum (24 subsections)
Section Pentanthera (2 subsections)
This subgenus includes the majority of the larger evergreen rhododendrons widely grown as ornamental plants. Some species, notably Rhododendron ponticum, have escaped from cultivation and become invasive in some regions such as New Zealand.