Rosebay Rhododendron Rhododendron maximum
Other Common Name(s):
- Phonetic Spelling
- rho-doh-DEN-dron MAKS-ih-mum
- This plant has high severity poison characteristics.
- See below
- Description
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Rhododendron maximum, commonly called rosebay rhododendron or great laurel, is a large, upright, loose, multi-stemmed, late-blooming, evergreen shrub that is native to North America from Ontario and Nova Scotia south to Ohio, Alabama and Georgia with a concentration of plants in the southern Appalachian Mountains where it typically grows in dense thickets which dominate the understory in some locations. It grows 10-20 feet. Shallow, fibrous root systems (do not cultivate around plants) will benefit greatly from a mulch (e.g., wood chips, bark or pine needles) to help retain moisture and stabilize soil temperatures.
The bark is thin, smooth and light brown on young trees. As the tree ages, thin scales develop.
Fire Risk: This plant has a medium flammability rating.
Seasons of Interest:
Blooms: Summer, Late summer Nut/Fruit/Seed: Fall
Insects, Diseases, or Other Plant Problems: Rhododendrons are susceptible to many insect and disease problems, including but not limited to canker, crown rot, root rot, leaf spot, rust, powdery mildew, aphids, borers, lacebugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips and whitefly. A healthy plant in the proper environment should have limited problems.
For suitable alternatives, see this video created by Charlotte Glen as part of the Plants, Pests, and Pathogens series.
VIDEO Created by Elizabeth Meyer for "Trees, Shrubs and Conifers" a plant identification course offered in partnership with Longwood Gardens.
- Profile Video:
- See this plant in the following landscape:
- Cultivars / Varieties:
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- 'Album'
- 'Purpureum'
- 'Red River'
- 'Summer Glow'
- 'Summer Solace'
- var. album
- var. purpureum
- var. roseum
- 'Album'
- 'Album', 'Purpureum', 'Red River', 'Summer Glow', 'Summer Solace', var. album, var. purpureum, var. roseum
- Tags:
- Cultivars / Varieties:
-
- 'Album'
- 'Purpureum'
- 'Red River'
- 'Summer Glow'
- 'Summer Solace'
- var. album
- var. purpureum
- var. roseum
- 'Album'
- 'Album', 'Purpureum', 'Red River', 'Summer Glow', 'Summer Solace', var. album, var. purpureum, var. roseum
- Tags:
-
-
Attributes:
- Genus:
- Rhododendron
- Species:
- maximum
- Family:
- Ericaceae
- Life Cycle:
- Woody
- Country Or Region Of Origin:
- North America
- Distribution:
- Ontario and Nova Scotia south to Ohio, Alabama, and Georgia
- Fire Risk Rating:
- medium flammability
- Wildlife Value:
- It proves winter and extreme weather coverage. Hummingbirds, butterflies, and bees are attracted to its blooms for nectar. Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli.
- Dimensions:
- Height: 5 ft. 0 in. - 15 ft. 0 in.
- Width: 5 ft. 0 in. - 12 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Native Plant
- Poisonous
- Shrub
- Tree
- Woody Plant Leaf Characteristics:
- Broadleaf Evergreen
- Habit/Form:
- Erect
- Open
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Cultural Conditions:
- Light:
- Deep shade (Less than 2 hours to no direct sunlight)
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- High Organic Matter
- Soil pH:
- Acid (<6.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- Available Space To Plant:
- 6-feet-12 feet
- NC Region:
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 3a, 3b, 4b, 4a, 5a, 5b, 6a, 6b, 7b, 7a
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Fruit:
- Display/Harvest Time:
- Fall
- Fruit Type:
- Capsule
- Fruit Description:
- Oblong seed capsule which splits open when ripe to release numerous seeds. Displays from September to October.
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Flowers:
- Flower Color:
- Green
- Orange
- Pink
- White
- Flower Inflorescence:
- Umbel
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Summer
- Flower Shape:
- Funnel
- Flower Size:
- 1-3 inches
- Flower Description:
- Flowers (to 2” across) of the Rosebay Rhododendron are rose-purplish to pink to white, often with olive green to orange spots. Flowers bloom in umbel-like inflorescences from June to August.
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Leaves:
- Woody Plant Leaf Characteristics:
- Broadleaf Evergreen
- Leaf Color:
- Green
- Leaf Feel:
- Leathery
- Smooth
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Leaf Margin:
- Entire
- Hairs Present:
- Yes
- Leaf Length:
- > 6 inches
- Leaf Description:
- Large, alternate, simple dark green and leathery with a smooth margin and rust covered hairs on the undersides. They can range from 4 to 8 inches long.
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Bark:
- Bark Color:
- Light Brown
- Surface/Attachment:
- Smooth
- Bark Description:
- The bark is thin, smooth and light brown on young trees. As the tree ages, thin scales develop.
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Stem:
- Stem Is Aromatic:
- No
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Landscape:
- Landscape Location:
- Houseplants
- Naturalized Area
- Woodland
- Landscape Theme:
- Butterfly Garden
- Pollinator Garden
- Winter Garden
- Attracts:
- Bees
- Butterflies
- Hummingbirds
- Pollinators
- Specialized Bees
- Problems:
- Poisonous to Humans
- Problem for Cats
- Problem for Dogs
- Problem for Horses
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-
Poisonous to Humans:
- Poison Severity:
- High
- Poison Symptoms:
- Salivation, watering of eyes and nose, abdominal pain, loss of energy, depression, nausea and vomiting, diarrhea, weakness, cardiac failure, difficult breathing, progressive paralysis of arms and legs, coma.
- Poison Toxic Principle:
- Andromedotoxin, Grayantoxin
- Causes Contact Dermatitis:
- No
- Poison Part:
- Bark
- Flowers
- Fruits
- Leaves
- Roots
- Seeds
- Stems
