Cold hardiness & minimum temperature

Is Moses-in-the-Cradle (Oyster Plant) (Tradescantia spathacea (syn. Rhoeo spathacea))cold hardy? Hardiness zone & min temp

Also called Moses-in-the-Cradle, Oyster Plant, Boat Lily, Moses in a Basket, Purple-Leaved Spiderwort, Cradle Lily.

More about moses-in-the-cradle (oyster plant)

About Moses-in-the-Cradle (Oyster Plant)

Tradescantia spathacea (syn. Rhoeo spathacea) · also called Moses-in-the-Cradle, Oyster Plant · houseplant

Moses-in-the-Cradle is a tough, clumping foliage houseplant grown for its rosettes of sword-shaped leaves, glossy green above and vivid purple beneath. Give it bright indirect light, water when the top inch of soil dries, and keep it above 50F (10C). The sap irritates skin, so it is best treated as mildly toxic around pets.

Cold limit: USDA 9a-11b (13-27 C)

What moses-in-the-cradle (oyster plant)'s hardiness rating actually means

Moses-in-the-Cradle (Oyster Plant) is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 9a-11b — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about 10 °C (sustained cold below this is damaging). Moses-in-the-Cradle (Oyster Plant) has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for moses-in-the-cradle (oyster plant) as it gets too cold:

Below about about 10 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can moses-in-the-cradle (oyster plant) go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when moses-in-the-cradle (oyster plant) can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Moses-in-the-Cradle (Oyster Plant) hardiness — frequently asked questions

Is moses-in-the-cradle (oyster plant) cold hardy?

Moses-in-the-Cradle (Oyster Plant) is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Moses-in-the-Cradle (Oyster Plant) can only live outside year-round in genuinely frost-free climates (roughly USDA 9a-11b); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature moses-in-the-cradle (oyster plant) can survive?

What hardiness zone is moses-in-the-cradle (oyster plant)?

Moses-in-the-Cradle (Oyster Plant) is rated USDA 9a-11b and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can moses-in-the-cradle (oyster plant) survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to moses-in-the-cradle (oyster plant) below its minimum temperature?

Below about about 10 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.