• Photo of Rhododendron (Rhododendrons)

Plant Profile: Rhododendron

Taxonomy: Rhododendron

Names

Azalea, Rhododendron, Rosebay

  • Photo of Rhododendron (Rhododendrons)

Phonetic Spelling:rho-doh-DEN-dron

Genus:Rhododendron

Species:

Family:Ericaceae

Woody shrubs, whether evergreen or deciduous, belong to the Ericaceae family. These plants thrive in moist, well-drained, acidic soils and prefer dappled sunlight. They are not suited for dense clay soils; therefore, it is advisable to enrich such soils with organic matter. Additionally, planting the root ball higher in the soil can improve drainage. Rhododendrons respond well to pruning after flowering and require minimal upkeep. They can serve as houseplants or be incorporated into landscapes as woody shrubs, fitting seamlessly as understory plants in forest woodlands or natural settings.

Wildlife Benefits: The flowers of these shrubs attract hummingbirds, while the genus Rhododendron provides support for the specialized bee species Andrena (Andrena) cornelli.

Insects, Diseases, and Other Plant Challenges: Rhododendrons are prone to various insect infestations and diseases. Common insect issues include aphids, borers, lacebugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips, and whiteflies. They may also suffer from diseases such as canker, crown rot, root rot, leaf spot, rust, and powdery mildew. Exposure to full sun can lead to leaf scorch, and poor drainage can cause root rot. However, with proper placement and care, a healthy plant should encounter few issues. It is worth noting that deer often cause damage to these plants.

 

Rhododendron Feature Summary

Rhododendron Image Gallery

Tags

#evergreen
#showy flowers
#deciduous
#understory
#nectar plant
#native bees
#woody
#low maintenance
#tsc
#dappled shade
#specialized bees
#cpp
#naturalizes
#pollinator plant
#problem for cats
#tsc-s
#problem for dogs
#bee friendly
#problem for horses
#woodlands

Similar Plants

Rhododendron is often confused with:

Rhododendron Feature Summary

Attributes
Throughout
Flowers attract humingbirds. Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli. Deer browse this plant.
Poisonous to Humans
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, cardiac failure, coma.
Andromedotoxin, Grayantoxin
Seeds
Leaves
Stems
Sap/Juice
Flowers
Bark
Fruits
Roots
Whole Plant Traits
Cultural Conditions
Dappled Sunlight (Shade through upper canopy all day)
Acid (<6.0)
Good Drainage
High Organic Matter
Loam (Silt)
Sand
Landscape
Small groups
Woodland
Naturalized Area
Pollinators
Specialized Bees
Hummingbirds
Problem for Cats
Problem for Dogs
Problem for Horses

Rhododendron Attributes

Rhododendron: Country Or Region Of Origin

USA, NC, Asia

Rhododendron: Distribution

Throughout

Rhododendron: Wildlife Value

Flowers attract humingbirds. Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli. Deer browse this plant.

Rhododendron: Life Cycle

Annual
Biennial
Bulb
Perennial
Woody

Rhododendron Poisonous to Humans

Rhododendron: 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, cardiac failure, coma.

Rhododendron: Poison Toxic Principle

Andromedotoxin, Grayantoxin

Rhododendron: Poison Severity

High
Low
Medium

Rhododendron: Causes Contact Dermatitis

No
Yes

Rhododendron: Poison Part

Bark
Flowers
Fruits
Leaves
Roots
Sap/Juice
Seeds
Stems

Rhododendron Whole Plant Traits

Rhododendron: Plant Type

Annual
Bulb
Carnivorous
Edible
Epiphyte
Fern
Ground Cover
Herb
Herbaceous Perennial
Houseplant
Mushroom
Native Plant
Ornamental Grasses and Sedges
Perennial
Poisonous
Rose
Shrub
Succulent
Tree
Turfgrass
Vegetable
Vine
Water Plant
Weed
Wildflower

Rhododendron: Woody Plant Leaf Characteristics

Broadleaf Evergreen
Deciduous
Needled Evergreen
Semi-evergreen

Rhododendron: Habit/Form

Arching
Ascending
Broad
Cascading
Climbing
Clumping
Columnar
Conical
Creeping
Dense
Erect
Horizontal
Irregular
Mounding
Multi-stemmed
Multi-trunked
Open
Oval
Prostrate
Pyramidal
Rounded
Spreading
Vase
Weeping

Rhododendron: Maintenance

Low
Medium
High

Rhododendron Cultural Conditions

Rhododendron: Light

Dappled Sunlight (Shade through upper canopy all day)
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)

Rhododendron: Soil pH

Acid (<6.0)
Alkaline (>8.0)
Neutral (6.0-8.0)

Rhododendron: Soil Drainage

Frequent Standing Water
Good Drainage
Moist
Occasional Flooding
Occasionally Dry
Occasionally Wet
Very Dry

Rhododendron: Soil Texture

Clay
High Organic Matter
Loam (Silt)
Sand
Shallow Rocky

Rhododendron Flowers

Rhododendron: Flower Color

filter_vintage
Pink
filter_vintage
White

Rhododendron: Flower Value To Gardener

Edible
Fragrant
Good Cut
Good Dried
Long Bloom Season
Long-lasting
Showy

Rhododendron: Flower Size

1-3 inches
3-6 inches
< 1 inch
> 6 inches

Rhododendron Leaves

Rhododendron: Woody Plant Leaf Characteristics

Broadleaf Evergreen
Deciduous
Needled Evergreen
Semi-evergreen

Rhododendron: Leaf Type

Compound (Pinnately , Bipinnately, Palmately)
Fronds
Needles
Sheath
Simple

Rhododendron: Leaf Arrangement

Alternate
Opposite
Other/more complex
Rosulate
Whorled

Rhododendron: Leaf Shape

Acicular
Auriculate
Cordate
Cuneate
Deltoid
Elliptical
Filiform
Lanceolate
Linear
Oblanceolate
Oblong
Obovate
Obtuse
Orbicular
Ovate
Palmasect
Palmatifid
Peltate
Pinnatifid
Pinnatisect
Reniform
Rhomboidal
Spatulate
Subcordate
Subulate

Rhododendron: Leaf Margin

Crenate
Crenulate
Dentate
Denticulate
Doubly Crenate
Doubly Dentate
Doubly Serrate
Entire
Lobed
Serrate
Sinuate
Undulate

Rhododendron: Hairs Present

No
Yes

Rhododendron: Leaf Feel

Fleshy
Glossy
Leathery
Papery
Prickly
Rough
Rubbery
Slippery
Smooth
Soft
Velvety
Waxy

Rhododendron Stem

Rhododendron: Stem Is Aromatic

No
Yes

Rhododendron Landscape

Rhododendron: Design Feature

Accent
Barrier
Border
Flowering Tree
Foundation Planting
Hedge
Mass Planting
Screen/Privacy
Security
Shade Tree
Small groups
Small Tree
Specimen
Street Tree
Understory Tree

Rhododendron: Landscape Location

Coastal
Container
Hanging Baskets
Houseplants
Lawn
Meadow
Naturalized Area
Near Septic
Patio
Pond
Pool/Hardscape
Recreational Play Area
Riparian
Rock Wall
Slope/Bank
Small Space
Vertical Spaces
Walkways
Woodland

Rhododendron: Attracts

Bats
Bees
Butterflies
Frogs
Hummingbirds
Moths
Pollinators
Predatory Insects
Reptiles
Small Mammals
Songbirds
Specialized Bees

Rhododendron: Problems

Allelopathic
Contact Dermatitis
Frequent Disease Problems
Frequent Insect Problems
Invasive Species
Malodorous
Messy
Poisonous to Humans
Problem for Cats
Problem for Children
Problem for Dogs
Problem for Horses
Short-lived
Spines/Thorns
Weak Wood
Weedy