Korean Rhododendron (Rhododendron mucronulatum)-Hort Answers - University of Illinois Extension
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University of Illinois Extension

Hort Answers


Korean Rhododendron
Rhododendron mucronulatum

Korean Rhododendron flowers
Korean Rhododendron flowers
Showy light purple to rosy pink flowers in early to mid spring; leaves are deciduous (shed in autumn), but they turn yellow and bronze before falling. 
Partial to full shade; moist, well-drained soil is best; needs acid soil. 
  • 'Cornell Pink'- Pink flowers.
  • 'Crater's Edge' - Dark red buds opening to lavender pink flowers.

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 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
Oval to rounded 
Native To:
China, Korea and Japan 
USDA Hardiness Zone
5 - 7 
Soil Conditions
Moist, Well-Drained
Exposure/Light Requirements
Full Shade
Partial Sun/Shade
Foliage Color
Fall Foliage Color
Pests and Problems
Additional Notes
Alkaline soils will lead to chlorosis (yellowing) of the leaves.


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