Thunbergia alata

RHS Plant Profile

black-eyed Susan

Other common names

black-eyed clock vine, bright eyes

Climber Wall Shrub Conservatory Greenhouse

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A moderately fast-growing, evergreen, perennial twining climber, often grown as an annual, to 2.5m tall with heart-shaped to oval toothed leaves. Flat, salver-shaped, orange to yellow flowers with dark brown centres are borne from summer to early autumn

Position

Full sun

Soil Types

Chalk, Clay, Loam

Max Height

1.5-2.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 1–2 years
Max Spread: 0.5-1 metres
Max Height: 1.5-2.5 metres

Growing Conditions

Chalk Clay Loam

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–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): H2

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Acanthaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Climbing
Genus: Thunbergia can be annuals or perennials, often twining climbers, with simple opposite leaves and trumpet-shaped or salver-shaped flowers borne singly in leaf axils, or in racemes, in summer
Name Status: Correct
Plant Range: Tropical Africa

How to Grow

Cultivation

Grow in well-drained soil in full sun with a support for the plant to climb

Propagation

Propagate by seed or if grown under glass, propagate by semi-ripe cuttings in late summer

Suggested planting locations and garden types

Cottage and informal garden
Patio and container plants
City and courtyard gardens
Flower borders and beds

Pruning

No pruning required outdoors. If grown under glass, pruning group 11

Pests

Aphids may cause problems and various pests such as glasshouse red spider mite, glasshouse whitefly and scale insects may be a problem under glass

Diseases

May be susceptible to powdery mildews