Mature size & growth rate

How big does Hound's Tongue Fern (Microsorum pustulatum) get?

Also called Hound's Tongue Fern, Hound's Tongue, Kangaroo Fern, Fragrant Fern.

More about hound's tongue fern

About Hound's Tongue Fern

Microsorum pustulatum · also called Hound's Tongue Fern, Hound's Tongue · houseplant

Microsorum pustulatum is an epiphytic Australasian fern with glossy, leathery, tongue-shaped fronds that spread from a creeping, scaly surface rhizome. It is considerably tougher than many indoor ferns, tolerating average humidity and lower light. Not individually listed by ASPCA; treat with caution around pets until formally assessed.

Mature size: Fronds typically 20-60 cm (8-24 in) long; plant spreads to 60-90 cm (2-3 ft) wide as the rhizome creeps.

Indoor size vs how big it gets in the wild

Hound's Tongue 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 20-60 cm (8-24 in) long. In the ground with no restriction it is a completely different plant — plant spreads to 60-90 cm (2-3 ft) wide 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

Hound's Tongue 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 with a balanced liquid fertiliser diluted to half strength every 4-6 weeks in spring and summer. ferns are light feeders; over-fertilising causes frond-tip burn. pause feeding in autumn and winter. skip feeding for several months after repotting into fresh mix.

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

How to keep hound's tongue fern smaller

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

Trim the longest vines back to the length you want — hound's tongue 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 hound's tongue 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 hound's tongue fern bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for hound's tongue fern the accelerators are:

More (indirect) light dramatically lengthens the vines and enlarges the leaves.
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 hound's tongue fern light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When hound's tongue fern outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for hound's tongue 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 hound's tongue fern repotting guide. If you want more of this plant instead of a bigger one, the hound's tongue fern propagation guide turns prunings into new plants.

Hound's Tongue Fern size — frequently asked questions

How big does hound's tongue fern get?

Hound's Tongue Fern reaches fronds typically 20-60 cm (8-24 in) long when grown indoors, and far larger where it grows unrestricted (plant spreads to 60-90 cm (2-3 ft) wide 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 hound's tongue fern slow or fast growing?

Hound's Tongue Fern is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Hound's Tongue 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 hound's tongue 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 hound's tongue fern smaller?

Trim the longest vines back to the length you want — hound's tongue 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 hound's tongue fern grow bigger or faster?

More (indirect) light dramatically lengthens the vines and enlarges the leaves. 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.