Asparagus fern vs Boston fern

Asparagus setaceus · Nephrolepis exaltata

Pet safety: Boston fern is listed non-toxic to cats and dogs; Asparagus fern is toxic (sapogenins). If the two are sold under the same name, a mislabelled plant is a genuine risk in a house with animals.

Why these two get mixed up

Boston fern is recorded here as a pet-safe alternative to Asparagus fern, so the question is usually whether the swap is actually a fair one.

Asparagus fern (Asparagus setaceus) — **Asparagus fern** — Asparagus setaceus. Photograph by Forest & Kim Starr, Wikimedia Commons , CC BY 3.0.

Boston fern (Nephrolepis exaltata) — **Boston fern** — Nephrolepis exaltata. Photograph by Wikimedia Commons contributor, Wikimedia Commons , CC BY-SA 3.0.

	Asparagus fern	Boston fern
Scientific name	Asparagus setaceus	Nephrolepis exaltata
Family	Asparagaceae	Polypodiaceae
Light floor	Medium	Low
Water	4–9 days	3–6 days
Humidity floor	40%	50%
Mature height	12–36 in	18–36 in
Habit	spreading	spreading
Growth rate	fast	moderate
Difficulty	Easy	Demanding
Toxic to pets	Yes	No
Typical price	$10–28	$15–40

Highlighted cells are where the two actually differ. Everything else they share.

The differences that matter

Pet safety

This is the difference that matters most. Boston fern is listed non-toxic to cats and dogs; Asparagus fern is toxic (sapogenins). If the two are sold under the same name, a mislabelled plant is a genuine risk in a house with animals.

Light

Boston fern tolerates low light; Asparagus fern needs medium as a floor. Put the second in the first's spot and it stretches and declines.

Difficulty

Asparagus fern scores 2 of 5, Boston fern scores 4. nothing about its light or soil is demanding, but it drops fronds within days in dry indoor air and never fully recovers from drying out once.

Not even related

Asparagus fern is Asparagaceae, Boston fern is Polypodiaceae. They share a shop label and nothing else — different families, different continents, different care.

Which should you buy?

With a cat or dog in the house, take Boston fern. The other is toxic, and if the shop label is wrong you will not know which you have brought home.
In a dim room, take Boston fern.
If you forget to water, take Asparagus fern, which goes 6 days between drinks.
If it is your first plant, take Asparagus fern, at 2 of 5.
For a small shelf, take either.

Full entries

Asparagus fern — care fields with sources, toxicity with every authority consulted, propagation and diagnosis. Boston fern — the same.

Sources

This database's own care records for Asparagus setaceus and Nephrolepis exaltata — every figure compared above.
Royal Botanic Gardens Kew, Plants of the World Online — accepted names and families for Asparagus setaceus and Nephrolepis exaltata
ASPCA Animal Poison Control — toxicity classification for both, cited on each species entry
Photographs: Wikimedia Commons, individually credited and licensed above

Compiled and edited by Tony Valcarcel · 2026-09-12
Every comparison above is drawn from a recorded field. Where the honest distinguisher is visual we show both photographs rather than describing a leaf we have no field for. How this is sourced.