Mature size & growth rate

How big does Licorice Fern (Polypodium glycyrrhiza) get?

Also called Licorice Fern, Licorice Root Fern.

More about licorice fern

About Licorice Fern

Polypodium glycyrrhiza · also called Licorice Fern, Licorice Root Fern · houseplant

Licorice fern is a small epiphytic Pacific Northwest native named for its sweet-tasting rhizomes. It naturally grows on mossy trunks and rocks, summer-dormant and winter-active. Indoors it wants cool, bright-indirect light, steady moisture, and high humidity. Give it a loose, bark-rich epiphytic mix and expect it to slow or drop fronds through warm, dry months.

Mature size: Fronds typically 15-40 cm long; spreads slowly across its container as the rhizome creeps.

Indoor size vs how big it gets in the wild

Licorice Fern 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 fronds typically 15-40 cm long. In the ground with no restriction it is a completely different plant — spreads slowly across its container as the rhizome creeps. — 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

Licorice Fern is a moderate grower. Realistically, expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Its feeding profile backs this up: feed lightly only during active growth (fall to spring) with a quarter- to half-strength balanced liquid fertiliser every 4-6 weeks. do not feed during summer dormancy. ferns are sensitive to salt buildup, so flush the mix occasionally.

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

How to keep licorice fern smaller

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

Trim the longest vines back to the length you want — licorice fern 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.
A trim once or twice a season is usually enough to hold its length.

The keep-it-smaller method, step by step

Decide the length you want. Pick the point each vine of licorice fern 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 licorice fern bigger or faster

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

When licorice fern outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for licorice fern:

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

Licorice Fern size — frequently asked questions

How big does licorice fern get?

Licorice Fern reaches fronds typically 15-40 cm long when grown indoors, and far larger where it grows unrestricted (spreads slowly across its container as the rhizome creeps.). 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 licorice fern slow or fast growing?

Licorice Fern is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Licorice Fern 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 licorice fern take to reach full size?

Roughly three to six years to reach mature indoor size, gaining a steady amount each growing season. Light, pot size and feeding move that timeline more than anything else.

How do I keep licorice fern smaller?

Trim the longest vines back to the length you want — licorice fern 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. A trim once or twice a season is usually enough to hold its length.

How can I make licorice fern 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.