Purple Rhododendron Rhododendron catawbiense

Catawba rhododendron in the Ericaceae (blueberry) family, is a large woody broadleaf evergreen, rounded to spreading, multi-stemmed shrub that often forms dense thickets.  It is native to the woodland slopes and ridges in the eastern United States along the Appalachian Mountain range, specifically in the Catawba region in the Blue Ridge Mountains. The genus name Rhododendron derives from the Greek words rhodo, meanin rose, and dendron, meaning tree.  

Plant this shrub in full to partial shade in acidic, rich, well-drained but moist soils. The root system is shallow so annual mulching will help retain moisture and keep soil temperatures even. It is important not to let the soil dry out completely or this will damage the roots. While it handles the morning sun, the plant does need protection from harsh afternoon rays and wind. It tolerates almost full shade conditions. Being from the mountain regions, it prefers cooler temperatures in the summer.

It typically grows from 6 to 10 feet tall, sometimes reaching heights of up to 20 feet. It may become sparse and rangy when grown in unfavorable conditions. The plant does tolerate pruning, but keep in mind that next season's blossoms will appear on old growth.

The flowers are attractive to hummingbirds, butterflies, and bees, so consider catawba rhododendron for butterfly and pollinator gardens. As an evergreen it adds interest in winter and gardens and naturalized areas. It can be a specimen, planted in small groups or mass planted and used as a hedge. 

Fire Risk: This plant has a high flammability rating and should not be planted within the defensible space of your home. Select plants with a low flammability rating for the sites nearest your home. 

Quick ID Hints:

• Long, leathery leaves, in tiers, congested at branch tips
• Large, 5-lobed bell-shaped flowers with maculations
• Terminal clusters of flowers in a raceme
• Juvenile twigs yellowish

Insects, Diseases, and Other Plant Problems:  Insect problems include aphids, borers, lace bugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips, and whitefly.  Diseases include canker, crown rot, root rot, leaf spot, rust, and powdery mildew. This plant is frequently damaged by deer.

While these shrubs remain very popular for landscape use, many cultivars are susceptible to Phytophthora root rot–this leads to leaf loss, reduced vigor, branch dieback, and wilting. Implement good cultural practices first, such as improving drainage with organic matter or berms and avoiding overwatering or overfertilization. For suitable alternatives, see this video created by Charlotte Glen as part of the Plants, Pests, and Pathogens series.

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common diseases of rhododendron.  

VIDEO Created by Elizabeth Meyer for "Trees, Shrubs and Conifers" a plant identification course offered in partnership with Longwood Gardens.

More information on Rhododendron.