Mature size & growth rate

How big does Red Clockvine (Thunbergia coccinea) get?

Also called Red Clockvine, Scarlet Clockvine, Scarlet Thunbergia.

More about red clockvine

About Red Clockvine

Thunbergia coccinea · also called Red Clockvine, Scarlet Clockvine · tropical

Thunbergia coccinea is a stunning tropical vine from the Indian subcontinent bearing pendant racemes of scarlet-orange tubular flowers with a yellow throat from autumn through spring. Fast-growing and hummingbird-attracting, it excels on pergolas and large trellises in warm climates or as a spectacular conservatory climber in cooler regions.

Mature size: 4–8 m in cultivation; up to 10 m in ideal tropical conditions

Watch for — 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.

Indoor size vs how big it gets in the wild

Red Clockvine does not get tall — it gets long. Size here is about stem length and how you train or cut it, not how much floor it claims. Indoors and in a pot, expect 4–8 m in cultivation. In the ground with no restriction it is a completely different plant — up to 10 m in ideal tropical conditions — which is why the pot, the light and the pruning matter so much for the size you actually end up with.

Growth shows up as lengthening stems that trail down or climb up a support; the plant can be kept tiny or grown metres long from the exact same root system.

Growth rate and years to mature

Red Clockvine is a fast grower. Realistically, expect one to three growing seasons — fast vines can add a metre or more of stem in a single good summer. Its feeding profile backs this up: 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.

Want this turned into the right next pot at the right moment? The pot size calculator and the red clockvine repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast red clockvine grows.

How to keep red clockvine smaller

You are not stuck with the maximum size. For red clockvine specifically, these are the levers, in order of impact:

Trim the longest vines back to the length you want — red clockvine takes hard cutting well and bushes out from the cut.
Cut just above a leaf node; each trimmed stem usually branches into two, so pruning makes it fuller, not sparser.
The cuttings root easily in water or mix, so "keeping it smaller" doubles as free new plants.
Expect to tidy it every few weeks in summer — this is a fast vine that will sprawl if left.

The keep-it-smaller method, step by step

Decide the length you want. Pick the point each vine of red clockvine should stop — you can be aggressive; it regrows readily.
Cut just above a node. Snip about 0.5 cm above a leaf node so the stem branches there instead of dying back.
Root the cuttings. Drop the trimmed pieces in water or mix — they root in 2-4 weeks and can fill the same pot for a bushier look.
Repeat as it runs. Re-trim whenever it overshoots; regular light pruning keeps it both smaller and fuller.

How to grow red clockvine bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for red clockvine the accelerators are:

Good light plus a moss pole or trellis triggers the longest, fastest, largest-leaved growth.
Give it something to climb — many vines grow far faster and bigger up a support than trailing.
Feed through spring and summer and keep it consistently watered while it is actively running.

Light is almost always the ceiling. The red clockvine light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When red clockvine outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for red clockvine:

Vines pooling on the floor or wrapping past where you want them — purely a trimming cue, not a repot one.
Bare, leggy stems with leaves only at the tips (usually a light problem, not a size one).
A tangled mass that has outrun its support and needs cutting back and re-training.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the red clockvine repotting guide. If you want more of this plant instead of a bigger one, the red clockvine propagation guide turns prunings into new plants.

Red Clockvine size — frequently asked questions

How big does red clockvine get?

Red Clockvine reaches 4–8 m in cultivation when grown indoors, and far larger where it grows unrestricted (up to 10 m in ideal tropical conditions). Growth shows up as lengthening stems that trail down or climb up a support; the plant can be kept tiny or grown metres long from the exact same root system.

Is red clockvine slow or fast growing?

Red Clockvine is a fast grower. Expect one to three growing seasons — fast vines can add a metre or more of stem in a single good summer. Red Clockvine does not get tall — it gets long. Size here is about stem length and how you train or cut it, not how much floor it claims.

How long does red clockvine take to reach full size?

Roughly one to three growing seasons — fast vines can add a metre or more of stem in a single good summer. Light, pot size and feeding move that timeline more than anything else.

How do I keep red clockvine smaller?

Trim the longest vines back to the length you want — red clockvine takes hard cutting well and bushes out from the cut. Cut just above a leaf node; each trimmed stem usually branches into two, so pruning makes it fuller, not sparser. The cuttings root easily in water or mix, so "keeping it smaller" doubles as free new plants. Expect to tidy it every few weeks in summer — this is a fast vine that will sprawl if left.

How can I make red clockvine grow bigger or faster?

Good light plus a moss pole or trellis triggers the longest, fastest, largest-leaved growth. Give it something to climb — many vines grow far faster and bigger up a support than trailing. Feed through spring and summer and keep it consistently watered while it is actively running.