Cast iron plant vs ZZ plant

Aspidistra elatior · Zamioculcas zamiifolia

Pet safety: Cast iron plant is listed non-toxic to cats and dogs; ZZ plant is toxic (insoluble calcium oxalates). 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

ZZ plant is recorded here as a pet-safe alternative to Cast iron plant, so the question is usually whether the swap is actually a fair one.

Cast iron plant (Aspidistra elatior) — **Cast iron plant** — Aspidistra elatior. Photograph by frau-doktor, Wikimedia Commons , Public domain.

ZZ plant (Zamioculcas zamiifolia) — **ZZ plant** — Zamioculcas zamiifolia. Photograph by User:WeFt, Wikimedia Commons , CC BY-SA 3.0.

	Cast iron plant	ZZ plant
Scientific name	Aspidistra elatior	Zamioculcas zamiifolia
Family	Asparagaceae	Araceae
Light floor	Low	Low
Water	10–14 days	14–21 days
Humidity floor	30%	20%
Mature height	18–30 in	24–36 in
Habit	clumping	upright
Growth rate	slow	slow
Difficulty	Easy	Easy
Toxic to pets	No	Yes
Typical price	$25–60	$18–40

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. Cast iron plant is listed non-toxic to cats and dogs; ZZ plant is toxic (insoluble calcium oxalates). If the two are sold under the same name, a mislabelled plant is a genuine risk in a house with animals.

Watering

Cast iron plant wants water every 10–14 days, ZZ plant every 14–21. On one shared watering schedule, one of them drowns.

Habit

Cast iron plant grows clumping; ZZ plant grows upright. That decides where each one physically works.

Not even related

Cast iron plant is Asparagaceae, ZZ plant is Araceae. 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 Cast iron plant. 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 either — both have a low light floor.
If you forget to water, take ZZ plant, which goes 18 days between drinks.
If it is your first plant, take either — both score 1 of 5.
For a small shelf, take Cast iron plant, which stops around 30 inches.

Full entries

Cast iron plant — care fields with sources, toxicity with every authority consulted, propagation and diagnosis. ZZ plant — the same.

Sources

This database's own care records for Aspidistra elatior and Zamioculcas zamiifolia — every figure compared above.
Royal Botanic Gardens Kew, Plants of the World Online — accepted names and families for Aspidistra elatior and Zamioculcas zamiifolia
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.