Wax plant vs Sweetheart hoya

Hoya carnosa · Hoya kerrii

Mature size: Wax plant reaches about 144 inches; Sweetheart hoya tops out near 96. Buying the wrong one for a shelf means rehoming it in a year.

Why these two get mixed up

Both are Hoya, so they arrive on the same shelf under near-identical labels and are routinely swapped in the trade.

Wax plant (Hoya carnosa) — **Wax plant** — Hoya carnosa. Photograph by Yvan leduc, Wikimedia Commons , CC BY-SA 3.0.

Sweetheart hoya (Hoya kerrii) — **Sweetheart hoya** — Hoya kerrii. Photograph by Hobbykafe, Wikimedia Commons , CC BY-SA 3.0.

	Wax plant	Sweetheart hoya
Scientific name	Hoya carnosa	Hoya kerrii
Family	Apocynaceae	Apocynaceae
Light floor	Medium	Medium
Water	10–18 days	12–21 days
Humidity floor	40%	40%
Mature height	12–144 in	6–96 in
Habit	trailing	climbing
Growth rate	moderate	slow
Difficulty	Easy	Easy
Toxic to pets	No	No
Typical price	$15–60	$15–50

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

The differences that matter

Mature size

Wax plant reaches about 144 inches; Sweetheart hoya tops out near 96. Buying the wrong one for a shelf means rehoming it in a year.

Habit

Wax plant grows trailing; Sweetheart hoya grows climbing. That decides where each one physically works.

Which should you buy?

In a dim room, take either — both have a medium light floor.
If you forget to water, take Sweetheart hoya, which goes 16 days between drinks.
If it is your first plant, take either — both score 2 of 5.
For a small shelf, take Sweetheart hoya, which stops around 96 inches.

Full entries

Wax plant — care fields with sources, toxicity with every authority consulted, propagation and diagnosis. Sweetheart hoya — the same.

Sources

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