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Rhododendron maximum

Phonetic Spelling
rho-doh-DEN-dron MAKS-ih-mum
This plant has high severity poison characteristics.
See below
Description

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 typically grows to 5-15’ tall, but infrequently to 30-40’ tall in the heart of its native habitat.  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. 

Regions:  Mountain, Piedmont

Seasons of Interest: 

  Blooms:   Summer, Late summer           Nut/Fruit/Seed:  Fall

Wildlife Value:    This plant is moderately resistant to damage from deer.  It proves winter and extreme weather coverage.  Hummingbirds, butterflies, and bees are attracted to its blooms.  Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli.

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.

Cultivars:
  • 'Album'
  • 'Purpureum'
  • 'Red River'
  • 'Summer Glow'
  • 'Summer Solace'
  • var. album
  • var. purpureum
  • var. roseum
Tags:
#bees#hummingbirds#butterflies#evergreen#pollinators#wildlife plant#showy#shade tolerant#nectar plant#woodland garden#winter interest#fall interest#specialized bees
Cultivars:
  • 'Album'
  • 'Purpureum'
  • 'Red River'
  • 'Summer Glow'
  • 'Summer Solace'
  • var. album
  • var. purpureum
  • var. roseum
Tags:
#bees#hummingbirds#butterflies#evergreen#pollinators#wildlife plant#showy#shade tolerant#nectar plant#woodland garden#winter interest#fall interest#specialized bees
  • 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
    Wildlife Value:
    This plant is moderately resistant to damage from deer.  It proves winter and extreme weather coverage.  Hummingbirds, butterflies, and bees are attracted to its blooms.  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.
  • Whole Plant Traits:
    Plant Type:
    Native Plant
    Poisonous
    Shrub
    Leaf Characteristics:
    Broadleaf Evergreen
    Habit/Form:
    Erect
    Open
  • Cultural Conditions:
    Light:
    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
    Available Space To Plant:
    6-feet-12 feet
    NC Region:
    Mountains
    Piedmont
    Usda Plant Hardiness Zone:
    3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b
  • Fruit:
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
    Fruit Description:
    Oblong seed capsule which splits open when ripe to release numerous seeds.
  • 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 early July.
  • Leaves:
    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.
  • 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.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Location:
    Houseplants
    Naturalized Area
    Woodland
    Landscape Theme:
    Winter Garden
    Attracts:
    Bees
    Butterflies
    Hummingbirds
    Pollinators
    Specialized Bees
    Problems:
    Poisonous
  • Poison:
    Poison Severity:
    High
    Poison Symptoms:
    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.
    Poison Toxic Principle:
    Andromedotoxin
    Causes Contact Dermatitis:
    No
    Poison Part:
    Bark
    Flowers
    Fruits
    Leaves
    Roots
    Seeds
    Stems