Crown of thorns vs Elephant bush

Euphorbia milii · Portulacaria afra

Pet safety: Elephant bush is listed non-toxic to cats and dogs; Crown of thorns is toxic (diterpene esters in the latex).

Why these two get mixed up

Elephant bush is recorded here as a pet-safe alternative to Crown of thorns, so the question is usually whether the swap is actually a fair one.

Crown of thorns (Euphorbia milii) — **Crown of thorns** — Euphorbia milii. Photograph by Matt Kieffer, Wikimedia Commons , CC BY-SA 4.0.

Elephant bush (Portulacaria afra) — **Elephant bush** — Portulacaria afra. Photograph by Frank Vincentz, Wikimedia Commons , CC BY-SA 3.0.

	Crown of thorns	Elephant bush
Scientific name	Euphorbia milii	Portulacaria afra
Family	Euphorbiaceae	Didiereaceae
Light floor	Bright indirect	Bright indirect
Water	10–21 days	10–21 days
Humidity floor	20%	20%
Mature height	12–36 in	12–72 in
Habit	upright	upright
Growth rate	moderate	fast
Difficulty	Easy	Easy
Toxic to pets	Yes	No
Typical price	$12–40	$10–35

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. Elephant bush is listed non-toxic to cats and dogs; Crown of thorns is toxic (diterpene esters in the latex). If the two are sold under the same name, a mislabelled plant is a genuine risk in a house with animals.

Mature size

Elephant bush reaches about 72 inches; Crown of thorns tops out near 36. Buying the wrong one for a shelf means rehoming it in a year.

Not even related

Crown of thorns is Euphorbiaceae, Elephant bush is Didiereaceae. 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 Elephant bush. 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 bright-indirect light floor.
If you forget to water, take either.
If it is your first plant, take Elephant bush, at 1 of 5.
For a small shelf, take Crown of thorns, which stops around 36 inches.

Full entries

Crown of thorns — care fields with sources, toxicity with every authority consulted, propagation and diagnosis. Elephant bush — the same.

Sources

This database's own care records for Euphorbia milii and Portulacaria afra — every figure compared above.
Royal Botanic Gardens Kew, Plants of the World Online — accepted names and families for Euphorbia milii and Portulacaria afra
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.