Pacific Rhododendron
Rhododendron macrophyllum
- Native to:
- Canada, United States
brewbooks (www.flickr.com) from near Seattle, USA
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Ericaceae
- Genus:
- Rhododendron
- Species:
- Rhododendron macrophyllum
- USDA Symbol:
- RHMA3
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Shrub , Tree
- Height:
- 760 cm
- Light Requirements:
- Part Shade,Shade
- Drought Tolerance:
- Low
- Bloom Months:
- apr,may,jun,jul
- Bloom Colors:
- pink, rose, white
- Landscaping Shrub:
- Yes
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★☆ Butterfly & moth species supported by this genus (NWF)
Host Plant for Caterpillars
Reported Fauna Sightings
Garden & Ecology Notes
- Wildlife Value:
- hummingbirds, butterflies, native bees
- Deer Resistant:
- Yes
- Fragrant:
- Yes
- Fire Notes:
- Not fire-adapted; plants are typically killed by fire and slow to recolonize burned areas.
Soil Requirements
- Soil Type:
- rich, well-drained loamy soil
- pH:
- 4.5 - 6.0 (acidic to slightly acidic)
- Drainage:
- excellent drainage required
- Moisture:
- consistently moist
- Notes:
- prefers organic matter-rich environments
Propagation & Germination
- Stratification:
- None required
- Germination Time:
- 14–42 days
- Notes:
- Seeds require light for germination; surface sow on moist acidic medium. Very fine seed.
The above propagation data sourced from Claude AI
Pre-treatment: Seeds are soaked in a 1% hydrogen peroxide solution for 24 hours, rinsed, and then placed in water for an additional 24 hours. Following this, seeds are subjected to a 30-day cold, moist stratification at 1 to 3 °C. They can be placed in fine mesh bags in a covered container or sown into trays filled with stabilized medium plugs and sealed in plastic bags. Containers or trays are then placed in refrigeration at 1 to 3 °C. Stratified seeds in mesh bags should be rinsed or plugs moistened weekly. If mold is evident, seeds should be treated with 1% hydrogen peroxide.
Source: npn.rngr.net
ORGHPS Germination Guide: Sow @ 20°C. Seed germinates within 3 months * sprinkle seed on 10 cm damp sphagnum moss; cover with clear plastic pop bottle cut in half; transplant seedling to acidic mix in shade outdoors when 5 cm high; protect from rodents and give protection in cold frame first winter