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Black-eyed Susan Vine

Thunbergia alata, Acanthaceae

Sources last read 13 September 2026.

Not yet rated How forgiving it is has not been judged here yet.

Also called black-eyed clock vine, blackeyed Susan vine, bright eyes and Thunbergia.

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Toxicity is partly unassessed

  • Not assessed for cats. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Not assessed for dogs. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Not assessed for people. RHS publishes no harm statement for this plant. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.

What the sources say about its care

Light
Full sun
RHS · read 13 September 2026
Water
Moist but well-drained or Well-drained
RHS · read 13 September 2026
Humidity

No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.

ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%
Penn State Extension · read 13 September 2026
Temperature

How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.

H2 — 1–5°C 1–5 °C
RHS · read 13 September 2026
Soil
Chalk, Clay, Loam; pH Acid or Alkaline or Neutral
RHS · read 13 September 2026
Toxic to cats
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Toxic to dogs
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Harmful to people
No statement of harm to people is published for this plant; that absence is not evidence it is safe.
RHS · read 13 September 2026

Routine care

Propagation
Seed, stem cuttings
NC State Extension · read 13 September 2026
Sow seed, or for plants under glass, take semi-ripe cuttings during late summer.
RHS · read 13 September 2026
Pruning
Outdoors, pruning is not needed. Under glass, follow pruning group 11.
RHS · read 13 September 2026
Pests and diseases
Aphids can be troublesome; under glass, scale insects, glasshouse whitefly, glasshouse red spider mite and other pests can be too. Disease risk: powdery mildews.
RHS · read 13 September 2026

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About the plant

Thunbergia alata, commonly called black-eyed Susan vine, is a herbaceous perennial climbing plant species in the family Acanthaceae. It is native to Eastern Africa, and has been naturalized in other parts of the world.

From Wikipedia, CC BY-SA 4.0 · read 13 September 2026

Native range
Trop. & S. Africa, Madagascar
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Tropical & S. Africa, Madagascar
NC State Extension · read 13 September 2026
Tropical Africa
RHS · read 13 September 2026
Climate
seasonally dry tropical
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Growth form
climbing shrub
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Annual, Ground Cover, Vine; habit cascading, climbing, spreading
NC State Extension · read 13 September 2026
Climbing (evergreen)
RHS · read 13 September 2026
Size
Height 36–96 in; width 36–72 in
NC State Extension · read 13 September 2026
Height 1.5-2.5 metres; spread 0.5-1 metres after 1–2 years
RHS · read 13 September 2026
Flowering
Flowers gold/yellow, orange; blooms in fall, spring
NC State Extension · read 13 September 2026
Flowers orange in summer and autumn; yellow in summer and autumn
RHS · read 13 September 2026

More of the Acanthaceae family

Plants with similar care

Sources

What this does not cover

The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.

Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.

If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.