Mature size & growth rate

How big does Blue Potato Bush (Lycianthes rantonnetii) get?

Also called Blue Potato Bush, Paraguay Nightshade, Blue Solanum.

More about blue potato bush

About Blue Potato Bush

Lycianthes rantonnetii · also called Blue Potato Bush, Paraguay Nightshade · flowering

Lycianthes rantonnetii (formerly Solanum rantonnetii) is a South American shrub or scrambling climber smothered for months in small, bright violet-blue flowers with yellow centres, followed by small red berries. Vigorous and sun-loving, it thrives in warm gardens, on patios as a standard or scrambler, and in frost-prone climates as a container specimen. All parts are toxic.

Mature size: 1.5-3 m tall and wide; standards typically maintained at 1-1.5 m on a clear stem

Indoor size vs how big it gets in the wild

Blue Potato Bush 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 1.5-3 m tall and wide. In the ground with no restriction it is a completely different plant — standards typically maintained at 1-1.5 m on a clear stem — 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

Blue Potato Bush 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: feed with a high-potash liquid fertiliser (e.g., a tomato feed) every 7-10 days from spring through summer to support continuous flowering. a slow-release balanced fertiliser incorporated at repotting supplements liquid feeds. do not fertilise in autumn and winter.

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

How to keep blue potato bush smaller

You are not stuck with the maximum size. For blue potato bush specifically, these are the levers, in order of impact:

Trim the longest vines back to the length you want — blue potato bush 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 blue potato bush 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 blue potato bush bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for blue potato bush 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 blue potato bush light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When blue potato bush outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for blue potato bush:

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 blue potato bush repotting guide. If you want more of this plant instead of a bigger one, the blue potato bush propagation guide turns prunings into new plants.

Blue Potato Bush size — frequently asked questions

How big does blue potato bush get?

Blue Potato Bush reaches 1.5-3 m tall and wide when grown indoors, and far larger where it grows unrestricted (standards typically maintained at 1-1.5 m on a clear stem). 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 blue potato bush slow or fast growing?

Blue Potato Bush 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. Blue Potato Bush 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 blue potato bush 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 blue potato bush smaller?

Trim the longest vines back to the length you want — blue potato bush 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 blue potato bush 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.