Klondyke Azalea
Rhododendron 'Klondyke'
Ericaceae · broadleaf deciduous shrub · introduced
Last updated
A broad, upright, dense deciduous azalea reaching 8 feet in 10 years and ultimately 10 to 12 feet. Funnel-shaped flowers, 2⅜ to 3⅛ inches wide, strong orange suffused with reddish-orange and an orange-yellow blotch, carried in ball-shaped trusses of 8 to 15 blooms. Late-midseason flowering. A Knap Hill-Exbury hybrid bred at Exbury Garden, UK (RHS 58).
Three-season interest: distinctive deep brownish-red new growth in spring, orange flowers at midseason, and bronze autumn foliage. Hardy to -15°F (Zone 5b-8a). Full sun to part shade on acidic, well-drained soil (pH 4.5-6.0). Knap Hill-Exbury hybrids tolerate full sun well. Substantial ultimate size (10 to 12 feet) requires very generous spacing. Deciduous habit means bare stems in winter. Twenty-one diseases and 15 pests documented at the genus level. All parts contain grayanotoxins and are toxic if ingested.
Quick Facts
Root Colonization (Spring–Fall)
Infection at Bud Break
Apothecia Formation & Spore Release
Aecial Stage (Alternate Host)
+ 13 more — see full disease and pest lists below
Phenological Calendar
| Stage | Typical Window |
|---|---|
| Bud swell BBCH 01-03 | Mar 15-Apr 15 |
| Bloom start BBCH 61 | Apr 18-May 5 |
| Full bloom BBCH 65 | Apr 28-May 15 |
| Bloom end BBCH 69 | May 10-May 25 |
| Bud set BBCH 55-59 | Jul 15-Sep 15 |