Great Rhododendron
Rhododendron maximum
Last reviewed: June 2026
Rhododendron maximum is a large evergreen shrub native to eastern North America, producing clusters of white to pale pink flowers from June through August in shaded, moist woodland conditions.
Great Rhododendron is toxic to dogs and cats.
Listed as toxic by the ASPCA Animal Poison Control Center (opens in new tab) (last reviewed 2026-05-21). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435and your veterinarian's emergency line.
Pollinator Patch flags toxic plants so you can choose a pet-safe native alternative for your yard.
Great Rhododendron is listed as toxic to grazing livestock (cattle, sheep, and goats) at a moderate level by the USDA PLANTS Database (opens in new tab). This is a livestock indicator and is separate from pet toxicity.
Light
part shade
Water
high
Size
60"–180" H × 60"–180" W
Bloom
Jun, Jul, Aug
Native to
AL, CT, DE, GA and 16 more states
Pollinators
bees, butterflies, hummingbirds
Great rhododendron is a large native evergreen shrub that produces clusters of white to pale pink flowers in summer. This substantial plant maintains year-round structure and can serve as an excellent foundation or screening plant in partially shaded areas.
Growing Great Rhododendron
Grow Great Rhododendron in part shade and high water. Mature plants reach 60 to 180 inches tall and spread 60 to 180 inches wide. Expect moderate maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Great Rhododendron is an HOA-friendly choice. Maintenance level: moderate. Tidiness: 4 out of 5.
Works well in: front yard, foundation, mid zone.
- Very large mature size may overwhelm smaller properties
- Requires consistent moisture which may increase maintenance needs
Wildlife value
Host plant for Azalea sphinx moth.
The abundant summer blooms attract bees, butterflies, and hummingbirds. The dense evergreen foliage provides year-round shelter for birds and small wildlife.
Common questions
- Where does Rhododendron maximum naturally grow?
- Great Rhododendron is native to the eastern United States, ranging from Maine south to Georgia and Alabama, typically found in cool, moist mountain forests and ravines.
- When does Great Rhododendron bloom?
- Rhododendron maximum blooms from June through August, producing large clusters of white to pale pink flowers at the branch tips.
- What pollinators visit Great Rhododendron?
- The flowers attract various pollinators including bees, butterflies, and hummingbirds, with the large blooms providing nectar during summer months.
- What growing conditions does Rhododendron maximum prefer?
- This species thrives in partial shade to full shade with consistently moist, well-drained acidic soils, making it ideal for woodland gardens and naturalized areas.
- Is Great Rhododendron toxic to dogs?
- Yes. Great Rhododendron is listed as toxic to dogs by the ASPCA Animal Poison Control Center (aspca.org). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Great Rhododendron toxic to cats?
- Yes. Great Rhododendron is listed as toxic to cats by the ASPCA Animal Poison Control Center (aspca.org). If your cat has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Great Rhododendron toxic to livestock?
- Great Rhododendron is listed as toxic to grazing livestock such as cattle, sheep, and goats (moderate severity) by the USDA PLANTS Database. This is separate from pet (dog and cat) toxicity.
- Is Great Rhododendron HOA-friendly?
- Great Rhododendron is generally an HOA-friendly choice in the right placement, with moderate maintenance.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Pollinator Patch flags toxic plants like Great Rhododendron and shows pet-safe natives for your ecoregion instead.
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