Rhododendron catawbiense, commonly called Catawba rhododendron or mountain rosebay, is a large, rounded to spreading, multi-stemmed, broadleaf evergreen shrub that typically grows to 6-10’ (rarely to 20’) tall. It is native to the eastern U.S. from Maryland to Kentucky south to Alabama and Georgia. Funnel-shaped lavender-pink flowers have green to yellow-brown throat markings. Flowers bloom mid to late spring in compact showy terminal clusters. ‘Grandiflorum’ is a medium dense cultivar with deep, slightly shiny, green foliage. Its long lasting, large lilac-purple flowers have matching filaments and ginger-brown spotted throats.