Mature size & growth rate

How big does Asparagus fern (Asparagus aethiopicus) get?

Also called foxtail fern (Sprengeri), lace fern.

About Asparagus fern

Asparagus aethiopicus · also called foxtail fern (Sprengeri), lace fern · houseplant

Asparagus fern is not a true fern but a relative of edible asparagus, with feathery emerald foliage on arching stems. Hardy and forgiving but mildly toxic to pets and possessed of small thorns that scratch skin. Drops needles when stressed.

Asparagus aethiopicus from southern Africa; despite the name it is not a true fern but a member of the asparagus family, with feathery cladodes rather than true leaves and a fleshy water-storing tuberous root system.

Arching plumed stems with sharp spines; ASPCA lists it as toxic to cats and dogs, the red berries containing sapogenin steroids causing GI upset, and repeated skin contact can cause dermatitis.

Mature size: 60-90 cm tall and wide

Sources: aspca.org, en.wikipedia.org

Indoor size vs how big it gets in the wild

Asparagus 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 60-90 cm tall and 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

Asparagus 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: half-strength balanced feed monthly in growing season.

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

How to keep asparagus fern smaller

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

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

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

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Good light plus regular feeding maximises offset and runner production.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

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

When asparagus fern outgrows the room (or the pot)

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

Asparagus fern size — frequently asked questions

How big does asparagus fern get?

Asparagus fern reaches 60-90 cm tall and 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 asparagus fern slow or fast growing?

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

Divide the clump every year or two — splitting asparagus 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 asparagus fern grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Good light plus regular feeding maximises offset and runner production. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.