Cold hardiness & minimum temperature

Is Alternanthera reineckii 'Rosaefolia' (Alternanthera reineckii 'Rosaefolia')cold hardy? Hardiness zone & min temp

Also called pink telanthera, rosaefolia Alternanthera.

More about alternanthera reineckii 'rosaefolia'

About Alternanthera reineckii 'Rosaefolia'

Alternanthera reineckii 'Rosaefolia' · also called pink telanthera, rosaefolia Alternanthera · tropical

Alternanthera reineckii 'Rosaefolia' is a classic red-leaved stem plant with elongated lance-shaped leaves, green above and pink-to-violet beneath. Taller and faster than the 'Mini' form, it makes a striking midground-to-background accent. Bright light, CO2 and iron-rich fertilisation are key to its rich coloration and steady, upright growth.

Cold limit: USDA Tropical aquarium plant; not frost-hardy, kept in heated aquaria (22-28°C)

What alternanthera reineckii 'rosaefolia''s hardiness rating actually means

Alternanthera reineckii 'Rosaefolia' 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 Tropical aquarium plant; not frost-hardy, kept in heated aquaria — 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). Alternanthera reineckii 'Rosaefolia' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for alternanthera reineckii 'rosaefolia' 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 alternanthera reineckii 'rosaefolia' 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 alternanthera reineckii 'rosaefolia' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Alternanthera reineckii 'Rosaefolia' hardiness — frequently asked questions

Is alternanthera reineckii 'rosaefolia' cold hardy?

Alternanthera reineckii 'Rosaefolia' 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. Alternanthera reineckii 'Rosaefolia' can only live outside year-round in genuinely frost-free climates (roughly USDA Tropical aquarium plant; not frost-hardy, kept in heated aquaria); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature alternanthera reineckii 'rosaefolia' can survive?

What hardiness zone is alternanthera reineckii 'rosaefolia'?

Alternanthera reineckii 'Rosaefolia' is rated USDA Tropical aquarium plant; not frost-hardy, kept in heated aquaria and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can alternanthera reineckii 'rosaefolia' 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 alternanthera reineckii 'rosaefolia' 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.