Rhododendron’Cosmopolitan’ (‘Cunningham’s White’ x ‘Vesuvius’) – A very cold-hardy cultivar that bears mid-pink blooms (with deep red spots on the throat) that fade to a paler pink as they mature. ‘Cosmopolitan’ features large glossy deep green leaves and a very dense growth habit. Although generally listed as zone 6 hardy, it may tolerate sheltered zone 5 sites. Grows 5-7′ high.
Rhododendron ‘Bubblegum’ (Chemically-induced Tetraploid of ‘Weston’s Anglo’) – This ‘PJM’-type rhododendron has larger blooms and denser foliage than its parent plant, ‘Weston’s Anglo’. The flowers emerge from deep pink buds (of an unmistakeable bubblegum colour), opening to bright mid-pink blooms with rose spotting. Grows 3′ high. Zone 5.
Rhododendron ‘Gartendirektor Glocker’ (‘Doncaster’ x R. williamsianum) – Bred by Hobbie back in 1952, this compact shrub produces deep rose-pink bell-shaped blooms and is very free-flowering, even at a young age. It has a dense, rounded growth habit with glossy green leaves (also rounded) that emerge with a bronze tint. Grows 3′ high. Zone 6.
Rhododendron ‘Hardijzer Beauty’ (R. racemosum x Kurume azalea) – Although technically an Azaleodendron (half azalea / half rhododendron), this floriferous shrub bears perfectly spherical trusses of funnel-shaped flowers that smother the plant in spring. The small green leaves turn a purplish-green in winter. Grows approximately 3′ high in 10 years. Zone 6.
Rhododendron ‘Cheer’ (‘Cunningham’s White’ x red R. catawbiense seedling) – A reliable rhododendron cultivar that is widely available. ‘Cheer’ features mid-spring blooms of medium-pink with a complimenting red blotch. The R. catawbiense lineage makes it quite hardy, so it is also tolerant of more exposed sites. Grows 5′ high by 6′ wide. Zone 6.