Red Clockvine (Scarlet Clockvine) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Requires full sun for best flowering. Six or more hours of direct sunlight daily encourages prolific bloom. In very hot tropical climates, light afternoon shade helps sustain flowering through the hottest months. Under glass, maximise winter light exposure. If your only bright window faces south, that's perfect for red clockvine — same window any aroid would fry on.

Watering

Watering red clockvine: every 3–5 days during active growth; reduce in winter. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Water regularly to keep the soil evenly moist during the growing season. Do not allow to dry out completely while in bud or flower, as drought stress causes bud drop. Reduce watering frequency in winter without allowing complete desiccation.

Soil and pot

Red Clockvine grows best in fertile, well-draining loam amended with organic matter. Prefers a rich, well-structured loam with excellent drainage. In containers use a peat-free compost blended with 20% perlite to aid drainage. pH 6.0–7.0. Apply a slow-release base dressing of compost when planting. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Red Clockvine sits happiest at around 60–80% humidity and 18–35 °C (65–95 °F). Prefers tropical humidity. In greenhouse or conservatory cultivation, mist regularly or use a pebble humidity tray, particularly during heated winter months. Ensure good air movement to prevent fungal diseases at high humidity. If you keep the room above 18–35 °C year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed red clockvine sparingly. Apply a balanced liquid fertiliser every 2–3 weeks throughout the main growing season (late spring to early autumn). Switch to a low-nitrogen, higher-potassium formulation from late summer to encourage flowering. Withhold feed in winter. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on red clockvine in the Growli community. Each is annotated with the most common cause so you know where to start.

• Poor flowering from over-pruning — T. coccinea blooms on the previous year's wood. Cutting back hard in autumn removes next season's flower buds. Prune lightly only after the flowering period has ended, removing dead or crossing stems.
• Aphids and mealybugs — Soft new shoot growth and flower buds attract aphid and mealybug colonies, especially under glass. Treat with insecticidal soap or neem oil spray, and introduce biological controls such as Aphidius parasitic wasps in enclosed glasshouses.
• Cold damage under glass — Even brief temperature drops below 10 °C cause leaf yellowing and stem dieback. Maintain a minimum night temperature of 13–15 °C in winter and keep the plant away from draughty vents or cold glass.

Propagation

Take semi-ripe stem cuttings 8–12 cm long in late spring or early summer. Remove lower leaves, dip in rooting hormone powder, and insert in moist perlite with bottom heat at 24–27 °C; roots form in 3–6 weeks. Seeds can be soaked for 24 hours then sown at 22–25 °C in spring. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Red Clockvine is mildly toxic to pets. Thunbergia coccinea is not individually listed by the ASPCA. The Acanthaceae family has no confirmed high-toxicity principle, but the species lacks individual ASPCA review. Treat as potentially irritating to pets if ingested and consult a vet if consumption occurs. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Red Clockvine deep-dive guides

Every aspect of red clockvine care, each with its own calibrated guide:

• Common red clockvine problems & fixes
• Red Clockvine watering schedule
• Red Clockvine light requirements
• Best soil mix for red clockvine
• Red Clockvine fertilizing guide
• When to repot red clockvine
• How to propagate red clockvine
• How to prune red clockvine
• What's eating my red clockvine?
• Red Clockvine growth rate & size
• Red Clockvine cold hardiness
• Red Clockvine temperature & humidity
• Is red clockvine toxic to cats & dogs?
• Is red clockvine toxic to cats?
• Is red clockvine toxic to dogs?
• All 8 Thunbergia varieties

Featured in these plant shortlists

Red Clockvine qualifies for 5 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best trailing & climbing houseplants — Vining and trailing houseplants for shelves, hanging pots, and moss poles — selected by growth habit.
• Best humidity-loving houseplants — Houseplants that thrive in a bathroom, kitchen, or by a humidifier — selected by documented humidity preference.
• Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
• Best fast-growing houseplants — Houseplants documented as fast or vigorous growers — quick to fill a pot, cover a pole or trail down a shelf.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Red Clockvine is also known as Red Clockvine, Scarlet Clockvine, and Scarlet Thunbergia.

• Comparettia falcata care — light, water and common problems
• Ionopsis utricularioides care — light, water and common problems
• Lepanthes telipogoniflora care — light, water and common problems
• All 8452 plant care guides in the Growli library