Rhododendron Catawbiense Grandiflorum is the database-clean form of the accepted cultivar Rhododendron ‘Catawbiense Grandiflorum’. It is a large Evergreen Ericaceae Shrub with a Bushy, Round habit. Broadly Elliptic, glossy Dark Green leaves provide year-round foliage. Rounded clusters of Funnel-shaped Lilac flowers carry Cinnamon-Brown speckles on the upper petals from late spring into early summer.
The RHS records an ultimate height and spread of 250-400 cm by 250-400 cm, reached in five to ten years. Missouri Botanical Garden records USDA zones 4-8 and May bloom, while the Québec Rhododendron Society records June flowering in Québec. Grow in sheltered Partial or dappled shade with North- or West-facing exposure. Use humus-rich, Moist but Well Drained, Acid Clay, Loam, or Sand. Avoid frost pockets, strong winds, drought, and waterlogging.
Do not allow the roots to dry out, and mulch annually, ideally with leaf mold. Propagate by semi-ripe cuttings in late summer, layering in fall, or grafting in winter. Minimal pruning is required. Use in city, courtyard, cottage, border, wall-side, woodland, specimen, group, or mass plantings. All consumer fruit fields remain blank because no qualifying exact-cultivar source documents consumer fruit traits. The plant is harmful if eaten by people and pets.
