Thunbergia

RHS Genus Guide

These vigorous, climbing annuals, with colourful flowers, are excellent for giving quick cover to arches and fences while you are waiting for longer-term plants to mature. Alternatively, allow them to cascade down from large hanging baskets. They cannot withstand frost.

Common name: Black-eyed Susan

RHS / Janet Cubey

Appearance

From summer to autumn, vigorous, twining stems carry 5-petalled trumpet flowers, in glowing shades of orange, yellow, red or creamy white. They open flat and often reveal dark chocolate-purple centres.

Preferences

They like any fertile soil that drains easily in full sun. In hanging baskets, use good quality compost with added perlite or vermiculite for good drainage.

Dislikes

Growth will be poor on very dry or wet soils. Plants will not flower in shade.

Did you know?

Besides the annuals, thunbergias also include some shrubs and evergreen climbers suitable for conservatories.

RHS Growing Guide

Growing guide

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How to grow thunbergia

RHS Recommended

Thunbergia

orange clock vine

Thunbergia gregorii

orange clock vine

Height: 2.5–4 metres
Width: 1–1.5 metres

Mysore clock vine

Thunbergia mysorensis

Mysore clock vine

Height: 4–8 metres
Width: 1.5–2.5 metres

Thunbergia alata 'Susie White Black Eye' (Susie Series)

Height
Width

black-eyed Susan

Thunbergia alata

black-eyed Susan

Height: 1.5–2.5 metres
Width: 0.5–1 metres

Thunbergia alata 'Susie Orange Black Eye' (Susie Series)

Height
Width

Thunbergia fragrans

Height
Width

blue trumpet vine

Thunbergia grandiflora

blue trumpet vine

Height: 4–8 metres
Width: 1.5–2.5 metres

black-eyed Susan 'African Sunset'

Thunbergia alata 'African Sunset'

black-eyed Susan 'African Sunset'

Height: 1.5–2.5 metres
Width: 0.5–1 metres

Award of Garden Merit

Plants for pollinators

See all Thunbergia