Rhododendron 

(roe-do-den' dron)

Common name: Florist's Azalea

Family: Ericaceae, Heath

Height x width: 1-6' or more x 1-4', generally 1'x1'

Foliage: various, generally 1' long, dark green, elliptical, brown pubescent

Flowers: trumpet-shaped terminal clusters, individual flowers to 1.5" across and 1' deep; generally red, pink, salmon, white and combinations; generally forced for Christmas through Mother's Day

Light: bright

Temperature: cool 60-65ºF

Watering: keep moist

Humidity: average

Soil: humusy, acidic, well-drained

Pests and Problems: leaf spots, root rots, spider mites, thrips; flowers and buds falling indicate improper watering or temperature; brown leaf margins indicate salts, improper watering; yellowing of foliage between veins indicates iron deficiency, often from too alkaline soil

Growth habit, uses: flowering potted plant, trained standard, bonsai

Other interest: native to Asia (species and cultivars for forcing), many being "Indian" types; this genus mainly contains outdoor shrubs, with much interbreeding and resulting taxonomic complexity and confusion

Other culture: water well in summer and feed regularly with azalea food; decrease watering in fall to encourage flowers; keep indoors, cool and bright; buds form in short days in warm, irregardless of daylength in cool (50-55ºF) in about 6 weeks; pinch off spindly new growth and sideshoots prior to bloom; keep cool (55-65ºF) during bloom or buds will drop off; keep pruned and fed, and place outdoors in summer; don't pinch after early summer

Propagation: stem and tip cuttings, may be difficult even with bottom heat


©Authored by Dr. Leonard Perry, Professor, University of Vermont as part of PSS121, Indoor Plants.

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