Not the plant you're looking for? Search over 300,000 plants

Shrubs

Rhododendron thomsonii

Thomson's rhododendron

An evergreen shrub or small tree, usually up to about 3m high in cultivation, though it can reach up to 6m in its native habitat. Bark is smooth, reddish and peeling, and leaves are rounded to oval, and matt dark green, with a bluish tint when young. Produces loose clusters of 3-10 bell-shaped, rich crimson flowers in mid to late spring

Save to My plants

Buy this plant

Plant nurseries
4 suppliers

Ultimate height

2.5–4 metres

Time to ultimate height

5–10 years

Ultimate spread

2.5–4 metres

Clay

Loam

Sand

Moisture

Moist but well–drained

pH

Acid

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Partial shade

Aspect

North–facing or West–facing

Exposure

Sheltered

Hardiness
Hardiness ratings
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
H1a: under glass all year (>15C)
H1b: can be grown outside in the summer (10 - 15)
H1c: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20)

Botanical details

Family: Ericaceae
Native to GB / Ireland: No
Foliage: Evergreen
Habit: Columnar upright, Spreading branched
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
Plant range: Myanmar to Himalaya and Tibet

How to grow

Cultivation

Grow in moist but well-drained, humus rich, acidic soil, in partial or dappled shade. Choose a site away from frost pockets and sheltered from strong winds; flowers may need protection from late frosts. Do not allow plants to dry out, and mulch annually, ideally with leaf mould. See rhododendron cultivation for more detailed advice

Propagation

Propagate by semi-ripe cuttings in late summer, by layering in autumn, or by grafting in winter

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Flower borders and beds
Wall side borders

Pruning

Minimal pruning required, see pruning group 8 (evergreens)

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 powdery mildews, honey fungus, silver leaf and Phytophthora, as well as more specific Rhododendron diseases

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.