Rhododendron oblongifolium
swamp azalea
A bushy deciduous shrub to 2.5m tall, with dark leaves glaucous beneath. Very fragrant, narrowly funnel-shaped white flowers, up to 4cm wide, flushed deep pink on the tube, open in early to mid summer
Other common names
swamp honeysucklewhite swamp honeysuckle
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Size
Ultimate height
1.5–2.5 metresTime to ultimate height
10–20 yearsUltimate spread
1.5–2.5 metresGrowing conditions
Moisture
Moist but well–drainedpH
AcidColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Blue Green | |||
|---|---|---|---|---|
| Summer | Pink White | Blue Green | ||
| Autumn | ||||
| Winter |
Position
- Full sun
- Partial shade
Aspect
South–facing or East–facing or West–facing
Exposure
Sheltered Hardiness
H6Botanical details
- Family
- Ericaceae
- Native to GB / Ireland
- No
- Foliage
- Deciduous
- Habit
- Bushy
- Potentially harmful
- Harmful if eaten. Wear gloves and other protective equipment when handling. Pets (dogs, cats, rabbits, tortoises) Harmful if eaten - for further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
- Genus
Rhododendron can be evergreen or deciduous shrubs or trees, with simple leaves, sometimes with a dense colourful indumentum of hairs on the lower side, and funnel-shaped, bell-shaped or tubular flowers that may be solitary or in short racemes
- Name status
Correct
- Horticultural Group
- Viscosa azaleas are lax deciduous shrubs with fairly small leaves and trusses of funnel-shaped, fragrant flowers in early summer
- Plant range
- Eastern N America
How to grow
Cultivation
Grow in moist but well-drained, leafy, humus-rich acid soil in part shade with shelter; sun tolerant if soil remains reliably moist; see rhododendron cultivation
Propagation
Propagate by seed when ripe, or semi-ripe cuttings in late summer, layering in autumn or grafting in late summer or late winter
Suggested planting locations and garden types
- City and courtyard gardens
- Cottage and informal garden
- Flower borders and beds
Pruning
Pests
May be susceptible to vine weevil, rhododendron and azalea whitefly, rhododendron leafhopper, pieris lacebug, scale insects, caterpillars and aphids
Diseases
May be susceptible to various Rhododendron diseases including powdery mildews, rhododendron petal blight, rhododendron bud blast, silver leaf and honey fungus
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