Black-Eyed Susan Vine / Clock Vine
Thunbergia alata
description
Black-Eyed Susan Vine is a vigorous warm-season climber with bright dark-centred flowers.
benefits
- Fast-growing
- Suitable for containers
How to care for Black-Eyed Susan Vine
sunlight
In its warm African habitat, Black-Eyed Susan Vine scrambles through open, sunny edges. Give it the brightest spot you have to keep the growth compact and the flowers coming.
Full sun
Ideal for flowering. Aim for about 4-6 hours of direct sun daily, such as a south- or west-facing window indoors, or a sunny outdoor position after frost has passed.
Bright indirect light - tolerated
It can grow in bright filtered light, but expect fewer flowers and longer, stretchier stems. Move it closer to the window if blooming slows.
watering
Keep Black-Eyed Susan Vine evenly moist while it is growing and flowering. Letting the root ball dry out can cause wilting and fewer blooms, but it should never sit in waterlogged soil.
Active growth and flowering
Water thoroughly about every 2-4 days in warm, bright weather, or when the top 1-2 cm of soil feels dry. Soak until water drains from the pot, then empty the saucer.
Cooler or lower-light months
When growth slows, water roughly every 7-14 days after the top few centimetres have dried. A smaller pot, porous terracotta, heat, bright light, and an actively growing root system all mean more frequent watering.
humidity
Preferred humidity
Native to warm tropical regions of East Africa, Black-Eyed Susan Vine grows best with moderately humid air. Average household humidity of about 40-50% is usually fine, but keep it away from heating vents and air conditioners.
Air that is too dry can cause brown, crisp leaf edges, drooping growth, and flower buds that dry up before opening. Dry air also makes spider mites more likely.
- Set the pot on a pebble tray with water, keeping the pot above the waterline.
- Give climbing stems room for airflow rather than crowding them against a wall or radiator.
temperature
Preferred temperature
Winter minimum
Native to warm tropical Africa, Black-Eyed Susan Vine grows best in steady warmth. Bring it indoors before cool autumn nights, and keep it away from frost. Growth slows below about 15°C (59°F), especially in low light.
nutrition
March - September
Feed every 2-4 weeks while it is actively climbing and flowering, using a balanced liquid fertiliser diluted to about half strength. Stop feeding when growth slows in autumn and winter, or if the plant is not producing new growth.
Nitrogen
Nitrogen supports the leafy growth needed to cover a trellis or basket. A balanced fertiliser provides enough, but avoid overfeeding, which can encourage leaves at the expense of flowers.
Potassium
Potassium supports flowering and overall vigour. A general fertiliser formulated for flowering plants can be useful once buds appear.
soil
Rich, moisture-retentive but free-draining soil
Black-Eyed Susan Vine grows fastest in fertile soil that stays lightly moist without becoming soggy. Use a quality potting mix with compost and perlite or coarse sand to keep roots aerated, especially in containers.
pH 6,0 - 7,0
This is slightly acidic to neutral, a range that supports steady nutrient uptake. Most general-purpose potting mixes suit it well; avoid strongly acidic mixes and refresh depleted container soil each season.