Swamp Azalea
Rhododendron viscosum
Also known as: Texas Azalea
- Native to:
- United States
John Torrey
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Ericaceae
- Genus:
- Rhododendron
- Species:
- Rhododendron viscosum
- USDA Symbol:
- RHVI2
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Shrub
- Height:
- 300 cm
- Light Requirements:
- Part Shade
- Drought Tolerance:
- Low
- Bloom Months:
- may,jun,jul
- Bloom Colors:
- white, pink
- Landscaping Shrub:
- Yes
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★☆ Butterfly & moth species supported by this genus (NWF)
Host Plant for Caterpillars
Azalea sphinx (Darapsa choerilus), Gypsy moth (Lymantria dispar), Hydrangea sphinx (Darapsa versicolor), tritona dagger moth (Acronicta tritona)
Garden & Ecology Notes
- Wildlife Value:
- butterflies, hummingbirds, bees
- Fragrant:
- Yes
- Fall Color:
- orange, red
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Can resprout from root crown following fire in wetland margins.
Soil Requirements
- Soil Type:
- moist, acidic, well-drained soil
- pH:
- 4.5 - 6.0 (acidic to slightly acidic)
- Drainage:
- excellent drainage required
- Moisture:
- consistently moist
- Notes:
- prefers organic-rich environments
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 60–90 days
- Germination Time:
- 14–42 days
- Notes:
- Seeds require light for germination. Surface sow on acidic medium and keep consistently moist.
The above propagation data sourced from Claude AI
Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).; then Cold-moist stratification for 90 days.
Notes: Seeds may require light for germination.
Source: Claude AI
ORGHPS Germination Guide: Requires light or the seed is very fine. Surface sow and expose to light. * 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