Carolina Rhododendron (Rhododendron carolinianum)-Hort Answers - University of Illinois Extension
University of Illinois Extension

University of Illinois Extension

Hort Answers


Carolina Rhododendron
Rhododendron carolinianum

Showy flowers (white, pink or rosy) in mid to late spring; mildly fragrant; leaves are evergreen and leathery; leaves do not change color in autumn, but can develop a purplish cast in winter in cold climates. 
Partial to full shade; moist, well drained soil is best; needs acid soil. 

This species is used as a parent in hybrids such as the P.J.M.Hybrids.

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. hardy zone 5-7.

'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. Hardy zone 5 to 7.

Mature Height
3-6 Feet
Mature Width
3-6 Feet
Mature Form
Native To:
United States 
USDA Hardiness Zone
6 - 7 
Soil Conditions
Moist, Well-Drained
Exposure/Light Requirements
Full Shade
Partial Sun/Shade
Foliage Color
Fall Foliage Color
Pests and Problems

Bacterial Disease

Environmental Damage

Fungal Disease

Herbicide Injury

Insect Damage

Additional pests and problems that may affect this plant:

Leaf spots, powdery mildew, scale, thrips, whitefly and other pests are possible problems.

Alkaline soils 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


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