Mature size & growth rate

How big does Crested Hart's Tongue Fern (Asplenium scolopendrium 'Crispum') get?

Also called Crested Hart's Tongue Fern, Crispum Hart's Tongue Fern, Hart's Tongue Fern.

More about crested hart's tongue fern

About Crested Hart's Tongue Fern

Asplenium scolopendrium 'Crispum' · also called Crested Hart's Tongue Fern, Crispum Hart's Tongue Fern · houseplant

A garden cultivar of the native European hart's tongue fern, grown for its distinctive strap-shaped, glossy evergreen fronds with attractively ruffled and crisped margins. It thrives in cool, moist, partially shaded spots in humus-rich, slightly alkaline to neutral, well-drained soil — limestone-derived soils are ideal. The most critical care point is ensuring consistent moisture without waterlogging, as both drought and soggy roots cause frond scorch and rot respectively. Asplenium scolopendrium is widely regarded as non-toxic to cats and dogs.

Mature size: 30–45 cm tall and wide (compact relative to the straight species).

Indoor size vs how big it gets in the wild

Crested Hart's Tongue Fern stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward. Indoors and in a pot, expect 30–45 cm tall and wide (compact relative to the straight species).. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Growth rate and years to mature

Crested Hart'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: apply a balanced, slow-release fertiliser in early spring and once more in midsummer; avoid high-nitrogen feeds that promote lush but weak growth.

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

How to keep crested hart's tongue fern smaller

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

Divide the clump every year or two — splitting crested hart's tongue fern is the main way to control its spread and refresh it.
Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump.
Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

The keep-it-smaller method, step by step

Lift the whole plant. Slide crested hart's tongue fern out of its pot in spring when the clump has filled it.
Split the clump. Tease or cut the rootball into two or more sections, each with healthy roots and growth.
Repot one division. Put a single division back in the original pot to reset it to a smaller size; pot or give away the rest.
Remove offsets as they form. Through the year, detach new runners or pups to stop it spreading again.

How to grow crested hart's tongue fern bigger or faster

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

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Brighter light speeds up clump and offset production noticeably.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

Light is almost always the ceiling. The crested hart's tongue fern light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

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

"Too big" usually arrives as one of these signs for crested hart's tongue fern:

The clump bulging over the pot rim or splitting the pot — the cue to divide, not to find a bigger room.
A dense centre that goes bare or tired while the edges keep spreading.
Runners or offsets escaping across the shelf or into neighbouring pots.

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

Crested Hart's Tongue Fern size — frequently asked questions

How big does crested hart's tongue fern get?

Crested Hart's Tongue Fern reaches 30–45 cm tall and wide (compact relative to the straight species). when grown indoors. Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Is crested hart's tongue fern slow or fast growing?

Crested Hart's Tongue Fern is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Crested Hart's Tongue Fern stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward.

How long does crested hart'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 crested hart's tongue fern smaller?

Divide the clump every year or two — splitting crested hart's tongue fern is the main way to control its spread and refresh it. Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump. Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

How can I make crested hart's tongue fern grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Brighter light speeds up clump and offset production noticeably. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.