Details of...
Scientific Name: Rhododendron (evergreen spp. & cvs.)
Pronunciation: roe-doe-DEN-drun
Common Name: rhododendron
Family Name: Ericaceae
Plant Type: Broadleaf evergreen
Key ID Features: Leaves alternate, usually leathery, mostly elliptic, 2-20 cm long x 1-7 cm wide, petioles 5-20 mm long; flowers up to 5 cm wide; corolla deeply 5-lobed, stamens 10.
Course(s): HORT 1155, Level 3 Apprenticeship

Habit: Dense, Spreading, Upright
Form: Oval - vertical
Texture: Coarse
Mature Size:
Height:7 - 10m
Spread:4 - 5m
Growth Rate:Slow
Origin: B.C. west of Cascades, U.S. - northwest
Hardiness Rating: Zone 6: (-23 to -18 C)
Exposure: Deep shade, Filtered shade, Part sun/part shade
Soil/ Growing Medium: Humus rich, Well-drained
Water Use: Low
Landscape Uses: Group or mass planting, Mixed shrub border, Screening, Specimen plant, Tall background, Woodland margin (Caution: poisonous parts)
Additional Info: Google. Species shown may include R. arizelum, R. formosanum, R. fortunei, and R. macrophyllum (see separate entries for other species and cultivars on campus). Description of common cultivars can be found at
Leaf Morphology: Glossary
Form: Simple
Arrangement: Alternate
Texture/ Venation: Leathery
Surfaces: Glabrous
Colour in Fall: Green
Leaf(let) Terms:
Shapes: Elliptic
Apices: Acuminate, Acute
Bases: Attenuate, Obtuse
Margins: Entire

Inflorescence Type: Floriferous, Raceme
Flower Morphology:Flowers perfect
Number of Petals:5
Corolla Shape:Campanulate
Ovary Position:Superior
Colour (petals): Showy, White, Pink, Orange, Yellow, Dark-red, Purple, Red
Flower Scent: None
Flower Time at Peak: May

Fruit Type: Capsule
Fruit Colour: Brown
Fruiting Time: Aug, Sep
Additional Info: Not showy, Persistent

Bark or Stem Colour:
Leaf Bud Type: Striate scales Outer scale centered directly over leaf scar)
Leaf Scar Shape:Crescent shaped
Organ Modifications: Fibrous-like roots, Forms a shallow tap root system when grown from seed

Propagation: Layering, Softwood cuttings, Seed
Plant Care:
Maintenance:Low maintenance plant
Other:Most hybrid cultivars will not form capsules (many gardeners find these unattractive and spend time removing them each spring).
Pest Susceptibility: Abiotic disorder, Beetles or weevils, Fungal leaf spot, Galls, Mildew, Root rot, ( Rabbit resistant )
(GAZ) GAZebo
(GAZE) GAZebo East : cv. Blue Diamond
(GAZW) GAZebo West : cv. Blue Diamond
(HPZ) Horticulture PlaZa : R. macrophyllum cv.
(MCF) Main Courtyard Fountain : cv. Vulcan (check ID)
(ONE) Overpass North side East : cv. Unique (?); R. impeditum
Location Map

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