Mature size & growth rate

How big does Macho Fern (Nephrolepis biserrata) get?

Also called Macho Fern, Giant Sword Fern, Bold Sword Fern.

More about macho fern

About Macho Fern

Nephrolepis biserrata · also called Macho Fern, Giant Sword Fern · houseplant

Nephrolepis biserrata, the macho fern, is a large, bold tropical fern producing long, wide, arching fronds with broad bright-green pinnae. Native to tropical regions worldwide, it is significantly larger than the Boston fern and excels in spacious interiors, shaded patios, and warm outdoor landscapes. Non-toxic to pets per ASPCA.

Mature size: 90–180 cm tall, 90–150 cm wide

Watch for — Overrunning containers: This is a vigorous fern that quickly becomes root-bound and sends out stolons that spill over pot edges. Repot annually in spring into a container two sizes larger, or divide the plant and repot sections. Outdoor specimens may need containment to prevent spreading.

Indoor size vs how big it gets in the wild

Macho 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 90–180 cm tall, 90–150 cm wide. 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

Macho 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 granular fertiliser in spring, supplemented by a monthly liquid feed at half-strength through summer. the large biomass benefits from regular nutrition. stop feeding in autumn and winter. avoid excess phosphorus, which can cause tip burn.

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

How to keep macho fern smaller

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

Divide the clump every year or two — splitting macho 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 macho 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 macho fern bigger or faster

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

When macho fern outgrows the room (or the pot)

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

Macho Fern size — frequently asked questions

How big does macho fern get?

Macho Fern reaches 90–180 cm tall, 90–150 cm wide 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 macho fern slow or fast growing?

Macho Fern is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Macho 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 macho 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 macho fern smaller?

Divide the clump every year or two — splitting macho 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 macho 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.