Mature size & growth rate

How big does Lemon Button Fern (Nephrolepis cordifolia 'Duffii') get?

Also called Button sword fern, Fishbone fern.

More about lemon button fern

About Lemon Button Fern

Nephrolepis cordifolia 'Duffii' · also called Button sword fern, Fishbone fern · houseplant

The Lemon Button Fern is a small, tidy sword fern with upright fronds lined by rounded, button-like leaflets and a faint lemony scent when brushed. More forgiving of average humidity than Boston ferns, it suits terrariums, desks and small pots. It likes moist soil and bright indirect light, and is pet-safe.

Mature size: Around 20-30 cm tall and wide, occasionally to 40 cm in a generous pot.

Watch for — Leggy, sparse fronds: Too little light. Move to brighter indirect light; though shade-tolerant, very low light thins growth and dulls colour.

Indoor size vs how big it gets in the wild

Lemon Button Fern grows on a tree's timeline and scale — indoors it becomes a tall, trunked statement plant rather than a tabletop one. Indoors and in a pot, expect around 20-30 cm tall and wide, occasionally to 40 cm in a generous pot.. 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.

It gains real height on a trunk or main stem, adding a tier of leaves a year and eventually reaching for the ceiling — this is a plant you grow up, not out.

Growth rate and years to mature

Lemon Button 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 monthly in spring and summer with a balanced liquid houseplant feed at half strength; this small fern needs little and is sensitive to fertiliser salts. reduce or pause in autumn and winter. flush the pot occasionally with plain water to clear salt buildup.

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

How to keep lemon button fern smaller

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

The decisive tool is the secateurs: lemon button fern can be topped (cut the main growing tip) to cap its height and force a bushier, shorter shape.
Keeping it deliberately pot-bound in a snug container slows the whole plant and limits ultimate size.
Prune in spring so it heals fast; remove the tallest leader back to a node to reset the height.
Expect to top or hard-prune it every year or two — left alone it heads for the ceiling.

The keep-it-smaller method, step by step

Pick the new height. Decide how tall you want lemon button fern and find a leaf node or branch point just below that.
Top the main stem. Cut the main growing tip cleanly just above that node in spring; this permanently caps the height and forces side branches.
Keep the pot snug. Avoid jumping to a much bigger pot — a slightly restricted rootball keeps the whole plant smaller.
Maintain the shape. Prune back the tallest new leaders each spring to hold it at the height you chose.

How to grow lemon button fern bigger or faster

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

It already wants the bright light it needs; warmth, a yearly pot-up and spring-summer feed are the accelerators.
Pot up a size every year or two while young; restricted roots are the main thing holding height back.
Feed regularly through the growing season and keep it warm — height comes from sustained good conditions.

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

When lemon button fern outgrows the room (or the pot)

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

The top leaves pressing against or bent by the ceiling — the classic "this is now too tall indoors" sign.
It has to be moved away from a light source it has literally outgrown.
Roots filling the largest pot you can reasonably keep indoors — at that point it is top-or-prune or move it outside (if hardy).

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

Lemon Button Fern size — frequently asked questions

How big does lemon button fern get?

Lemon Button Fern reaches around 20-30 cm tall and wide, occasionally to 40 cm in a generous pot. when grown indoors. It gains real height on a trunk or main stem, adding a tier of leaves a year and eventually reaching for the ceiling — this is a plant you grow up, not out.

Is lemon button fern slow or fast growing?

Lemon Button Fern is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Lemon Button Fern grows on a tree's timeline and scale — indoors it becomes a tall, trunked statement plant rather than a tabletop one.

How long does lemon button 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 lemon button fern smaller?

The decisive tool is the secateurs: lemon button fern can be topped (cut the main growing tip) to cap its height and force a bushier, shorter shape. Keeping it deliberately pot-bound in a snug container slows the whole plant and limits ultimate size. Prune in spring so it heals fast; remove the tallest leader back to a node to reset the height. Expect to top or hard-prune it every year or two — left alone it heads for the ceiling.

How can I make lemon button fern grow bigger or faster?

It already wants the bright light it needs; warmth, a yearly pot-up and spring-summer feed are the accelerators. Pot up a size every year or two while young; restricted roots are the main thing holding height back. Feed regularly through the growing season and keep it warm — height comes from sustained good conditions.