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Rhododendron 'Dr. A. Blok'

Common Name(s):

Phonetic Spelling
roh-do-DEN-dron
This plant has low severity poison characteristics.
See below
Description

'Dr. A. Blok' rhododendron is a compact, evergreen shrub in the Ericaceae (blueberry) family that typically grows to a maximum height and width of 7 feet. The genus name derives from the Greek words rhodo, which means rose, and dendron, meaning tree. 

Plant this cultivar in a location with partial or light shade and organically rich, acidic soils that drain well. It will not tolerate dense clay. This shrub will require regular watering, and the roots may rot if the soil does not drain well. Plant the root ball high in the soil to help with drainage. Avoid overwatering and over-fertilizing. Pruning, if desired, may be done after flowering.  

This plant makes a great addition to a shady border, as a low hedge, or an accent plant. Use it as an understory shrub in a woodland garden or naturalized area, or in a pollinator garden where its showy, bright pink flowers will attract bees.

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. This plant is frequently damaged by deer.

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.

More information on Rhododendron.

Profile Video:
See this plant in the following landscape:
Pond and Stream
Cultivars / Varieties:
Tags:
#evergreen#showy flowers#poisonous#shrub#pink flowers#low maintenance#spring flowers#accent plant#hedges#specialized bees#deer browsing plant#border planting#spring interest#acidic soils tolerant#pollinator plant#naturalized area#flowers late spring#evergreen shrub#compact habit#understory shrub#partial shade tolerant#problem for cats#problem for dogs#bee friendly#problem for horses#shrub borders#woodland garden#low hedge#flowers mid-spring
 
Cultivars / Varieties:
Tags:
#evergreen#showy flowers#poisonous#shrub#pink flowers#low maintenance#spring flowers#accent plant#hedges#specialized bees#deer browsing plant#border planting#spring interest#acidic soils tolerant#pollinator plant#naturalized area#flowers late spring#evergreen shrub#compact habit#understory shrub#partial shade tolerant#problem for cats#problem for dogs#bee friendly#problem for horses#shrub borders#woodland garden#low hedge#flowers mid-spring
  • Attributes:
    Genus:
    Rhododendron
    Family:
    Ericaceae
    Life Cycle:
    Woody
    Wildlife Value:
    Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli. Deer browse this plant.
    Dimensions:
    Height: 4 ft. 0 in. - 9 ft. 0 in.
    Width: 4 ft. 0 in. - 7 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Poisonous
    Shrub
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Habit/Form:
    Rounded
    Growth Rate:
    Medium
    Maintenance:
    Low
  • Cultural Conditions:
    Light:
    Dappled Sunlight (Shade through upper canopy all day)
    Soil Texture:
    High Organic Matter
    Soil pH:
    Acid (<6.0)
    Soil Drainage:
    Good Drainage
    Moist
    Available Space To Plant:
    3 feet-6 feet
    6-feet-12 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    6a, 6b, 7a, 7b, 8a, 8b
  • Fruit:
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
  • Flowers:
    Flower Color:
    Pink
    Flower Inflorescence:
    Raceme
    Flower Bloom Time:
    Spring
    Flower Shape:
    Funnel
    Flower Petals:
    4-5 petals/rays
    Flower Description:
    Hot pink flowers appear mid to late spring.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Leaf Color:
    Green
    Leaf Feel:
    Leathery
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Elliptical
    Leaf Margin:
    Entire
    Hairs Present:
    No
    Leaf Length:
    3-6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    Dark green leathery foliage.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Location:
    Naturalized Area
    Woodland
    Design Feature:
    Accent
    Border
    Hedge
    Attracts:
    Specialized Bees
    Problems:
    Poisonous to Humans
    Problem for Cats
    Problem for Dogs
    Problem for Horses
  • Poisonous to Humans:
    Poison Severity:
    Low
    Poison Symptoms:
    Vomiting (not in horses), diarrhea, weakness, cardiac failure
    Poison Toxic Principle:
    Grayantoxin
    Causes Contact Dermatitis:
    No