Catawba Rhododendron (Rhododendron catawbiense)-Hort Answers - University of Illinois Extension
University of Illinois Extension

University of Illinois Extension

Hort Answers

Shrub

Catawba Rhododendron
Rhododendron catawbiense

Catawba Rhododendron flowers
Catawba Rhododendron flowers
 
Features
Large clusters of flowers (color depends on cultivar selected) in late spring; leaves are evergreen and leathery. 
 
Culture
Partial to full shade; moist, well drained soil is best; needs acid soil. 
 
Cultivars

Incredible number of cultivars available. Check local nurseries for cultivars available in your area.

Common Groups of Hybrid Rhododendrons

'Girard' Hybrids: This large group of azaleas includes both deciduous and evergreen cultivars. They vary in flower color and winter hardiness.

'Knapp Hill' Hybrids: The result of crosssing several species of Rhododendron. A large group including 'Knapp Hill', 'Exbury', 'Slocock' and 'Ilam' Hybrids. These azaleas are deciduous. Flower color depends on the cultivar selected. Mildew can be a problem with this group. Hardiness zones 5 to 7.

'Northern Lights' Hybrids: Developed at University of Minnesota. These hybrids were selected for excellent cold hardiness (to -30 degrees). These azaleas are deciduous. Flower color depends on cultivar selected.

'P.J.M.' Hybrids:A group of hybrids that are known for their compact size (3-6 ffet) and their flower color (shades of lavender pink to mauve). These rhododendrons are evergreen, with the foliage taking on a purplish cast in winter. Hardiness zones 5 to 7.

 
 
Mature Height
6-12 Feet
 
Size
Medium
 
 
Mature Width
6-12 Feet
 
Mature Form
Usually rounded, but can become more upright and leggy. 
 
Native To:
United States 
 
USDA Hardiness Zone
4 - 7 
 
Soil Conditions
Moist, Well-Drained
 
 
Tolerance
 
 
Exposure/Light Requirements
Full Shade
Partial Sun/Shade
 
 
Uses
Border
Massing
Naturalizing
Screen
Specimen
 
 
Foliage Color
Green
 
 
Fall Foliage Color
Green
 
 
Pests and Problems

Bacterial Disease

Environmental Damage

Fungal Disease

Herbicide Injury

Insect Damage


Additional pests and problems that may affect this plant:

A number of diseases and insects can attack this species; the most serious are black vine weevil, borers, leaf blights and spots.

Alkaline soil will lead to chlorosis (yellowing) of the leaves; winter sun and wind can be damaging to the evergreen foliage.

 
Additional Notes
For more information on rhododendrons, visit the American Rhododendron Society website at www.rhododendron.org.

 

 
Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic