Rhododendron occidentale (Torr. & A. Gray) A. Gray
Ericaceae (Heath Family)
USDA Symbol: rhoc
A fragrant, loosely branched, spreading shrub that can reach 15 ft. in height but is usually 3-9 ft. tall. The bark is shredding. The leaves are thin, light green and oval. White, tubular flowers may be tinged pink and have a yellow-blotched upper lobe. Flowers occur in tightly compact clusters. A shrub with large, white to deep pink, very fragrant flowers in large clusters at stem ends.
Flower variations include mixtures of pale pink, deep pink, and yellow-orange. An evergreen, pink-flowered relative, California Rosebay (R. macrophyllum), grows from British Columbia to California and makes a choice ornamental; it is the state flower of Washington, where it is known as Red Rhododendron.
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Plant CharacteristicsDuration: Perennial
Size Class: 12-36 ft.
Bloom InformationBloom Color: White
Bloom Time: Apr , May , Jun , Jul , Aug
DistributionUSA: CA , OR
Native Distribution: CA mts. from Kern & Santa Cruz Cos., n. to s.w. OR
Native Habitat: Stream banks and other moist places below 7500 ft.
Growing ConditionsWater Use: High
Light Requirement: Part Shade
Soil Moisture: Moist
Soil pH: Acidic (pH<6.8)
CaCO3 Tolerance: None
Soil Description: Moist, well-drained soil.
Conditions Comments: A parent of many hybrid azaleas.
BenefitWarning: Rhododendrons contain poisonous substances and should not be ingested by humans or animals. Honey made from flowers also may be toxic. POISONOUS PARTS: All parts. Highly Toxic, May be Fatal if eaten. Symptoms include salivation, watering of eyes and nose, abdominal pain, loss of energy, depression, nausea and vomiting, diarrhea, weakness, difficult breathing, progressive paralysis of arms and legs, coma. Toxic Principle: Andromedotoxin. (Poisonous Plants of N.C.)
Conspicuous Flowers: yes
Value to Beneficial InsectsSpecial Value to Bumble Bees
This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
Butterflies and Moths of North America (BAMONA)Rhododendron occidentale is a larval host and/or nectar source for:
Hoary Comma |
Learn more at BAMONA
PropagationDescription: Combine seeds loosely with sphagnum moss and sprinkle lightly over a 2:1 perlite/peat mixture. Optimum temperatures for germination are 45-50 degrees. Transplant seedlings to acid soil with a high content of organic matter. Cultivated evergreen azaleas
Seed Treatment: No pretreatment is necessary.
Commercially Avail: yes
National Wetland Indicator Status
From the National Suppliers DirectoryAccording to the inventory provided by Associate Suppliers, this plant is available at the following locations:
Oregon Native Plant Nursery - Woodburn, OR
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Santa Barbara Botanic Garden - Santa Barbara, CA
BibliographyBibref 1186 - Field Guide to Moths of Eastern North America (2005) Covell, C.V., Jr.
Bibref 1185 - Field Guide to Western Butterflies (Peterson Field Guides) (1999) Opler, P.A. and A.B. Wright
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Additional resourcesUSDA: Find Rhododendron occidentale in USDA Plants
FNA: Find Rhododendron occidentale in the Flora of North America (if available)
Google: Search Google for Rhododendron occidentale
MetadataRecord Modified: 2010-11-23
Research By: TWC Staff