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Rhododendron yedoense var. poukhanense

Common Name(s):

Phonetic Spelling
rho-doh-DEN-dron yeh-DOH-en-see poo-KAH-nen-see
This plant has high severity poison characteristics.
See below
Description

Korean azalea is a woody, deciduous to semi-evergreen shrub in the Ericaceae (blueberry) family and native to central and southern Korea. This spreading shrub reaches a height of 3 to 6 feet and a width of 6 to 12 feet, maintaining its leaves in mild winters. It is the parent plant to many of the current hybrid evergreen azaleas. The genus name derives from the Greek words rhodo, which means rose, and dendron, meaning tree. Yedo, from the specific epithet yedoense, was the former city name of Tokyo, Japan.

Plant it in partial to full shade in moist, rich, well-drained soils. Good drainage is essential as wet feet can cause disease problems and root rot; however, the soil should not be allowed to dry out completely. A thick layer of organic mulch will help keep the soil moist and the temperature even for the best root growth. It will need protection from drying winter winds. 

It looks attractive planted in small groups in shrub borders, as an informal hedge, or planted along a foundation. Its showy fragrant flowers make it an excellent choice for specimen planting near a patio or walkway or in a pollinator or butterfly garden where the showy, pink- purple blooms will provide nectar for visiting butterflies and hummingbirds. 

Insects, Diseases, and Other Plant Problems: Insect problems include aphids, borers, lace bugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips, and whitefly. Diseases include canker, crown rot, root rot, leaf spot, rust, and powdery mildew, though Korean azalea has shown better resistance to Phytophthora root rot. This plant is frequently damaged by deer but tolerates browsing by rabbits.

While these shrubs remain very popular for landscape use, many cultivars are susceptible to Phytophthora root rot—this leads to leaf loss, reduced vigor, branch dieback, and wilting. Implement good cultural practices first, such as improving drainage with organic matter or berms and avoiding overwatering or overfertilization. However, if you have a site with a history of this disease, consider planting one of the root rot-resistant alternative species listed in the left-hand sidebar. 

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:
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Cultivars / Varieties:
Tags:
#hummingbirds#showy flowers#poisonous#fragrant flowers#specimen#semi-evergreen#purple flowers#deciduous shrub#rabbit resistant#mass planting#hedges#specialized bees#disease resistant#deer browsing plant#foundation planting#pollinator plant#walkway planting#small group plantings#patio planting#nectar plant late spring#butterfly friendly#nectar plant mid-spring#problem for cats#problem for dogs#problem for horses#fall color orange-red#shrub borders
 
Cultivars / Varieties:
Tags:
#hummingbirds#showy flowers#poisonous#fragrant flowers#specimen#semi-evergreen#purple flowers#deciduous shrub#rabbit resistant#mass planting#hedges#specialized bees#disease resistant#deer browsing plant#foundation planting#pollinator plant#walkway planting#small group plantings#patio planting#nectar plant late spring#butterfly friendly#nectar plant mid-spring#problem for cats#problem for dogs#problem for horses#fall color orange-red#shrub borders
  • Attributes:
    Genus:
    Rhododendron
    Species:
    yedoense
    Family:
    Ericaceae
    Life Cycle:
    Woody
    Country Or Region Of Origin:
    Korea
    Wildlife Value:
    Flowers attract butterflies and hummingbirds. Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli.
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Phytophthora root rot
    Dimensions:
    Height: 3 ft. 0 in. - 6 ft. 0 in.
    Width: 6 ft. 0 in. - 12 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Poisonous
    Shrub
    Woody Plant Leaf Characteristics:
    Deciduous
    Semi-evergreen
    Habit/Form:
    Spreading
    Maintenance:
    Medium
  • Cultural Conditions:
    Light:
    Dappled Sunlight (Shade through upper canopy all day)
    Deep shade (Less than 2 hours to no direct sunlight)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    High Organic Matter
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Soil Drainage:
    Good Drainage
    Moist
    Available Space To Plant:
    12 inches-3 feet
    6-feet-12 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    4a, 4b, 5b, 5a, 6b, 6a, 7b, 7a, 8a, 8b, 9b, 9a
  • Fruit:
    Fruit Type:
    Capsule
    Fruit Description:
    Dry capsule
  • Flowers:
    Flower Color:
    Pink
    Purple/Lavender
    Flower Inflorescence:
    Raceme
    Flower Value To Gardener:
    Fragrant
    Showy
    Flower Bloom Time:
    Spring
    Flower Shape:
    Funnel
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    1-3 inches
    Flower Description:
    Showy slighly fragrant 2 inch pink purple flowers with a dark blotch on each of 5 petals. Flowers appear in clusters of 2-4 from April-May
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Semi-evergreen
    Leaf Color:
    Green
    Deciduous Leaf Fall Color:
    Orange
    Red/Burgundy
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Margin:
    Entire
    Hairs Present:
    No
    Leaf Description:
    Dark green simple alternate leaves with entire margins. Attractive red-orange fall color.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Location:
    Patio
    Walkways
    Woodland
    Landscape Theme:
    Butterfly Garden
    Pollinator Garden
    Design Feature:
    Foundation Planting
    Hedge
    Mass Planting
    Small groups
    Specimen
    Attracts:
    Butterflies
    Hummingbirds
    Specialized Bees
    Resistance To Challenges:
    Diseases
    Rabbits
    Problems:
    Poisonous to Humans
    Problem for Cats
    Problem for Dogs
    Problem for Horses
  • 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, difficult breathing, progressive paralysis of arms and legs, coma
    Poison Toxic Principle:
    Grayanotoxins, Andromedotoxin
    Causes Contact Dermatitis:
    No
    Poison Part:
    Bark
    Flowers
    Fruits
    Leaves
    Roots
    Sap/Juice
    Seeds
    Stems