Cold hardiness & minimum temperature

Is Kohleria 'Dark Velvet' (Kohleria 'Dark Velvet')cold hardy? Hardiness zone & min temp

Also called dark velvet kohleria.

More about kohleria 'dark velvet'

About Kohleria 'Dark Velvet'

Kohleria 'Dark Velvet' · also called dark velvet kohleria · flowering

Kohleria 'Dark Velvet' is a rhizomatous gesneriad cultivar grown for its deep, velvety dark-green to bronze leaves and red-spotted tubular flowers. Like other kohlerias it spreads by scaly water-storing rhizomes that make it resilient, and it flowers over a long season in bright indirect light, warmth, and steady moisture, provided its fuzzy leaves stay dry.

Cold limit: USDA 10-11 (grown indoors in most US homes) · RHS H1b (18-27°C)

Watch for — Winter dieback: A natural semi-dormancy of the rhizomes rather than death. Keep them barely moist and warm; new shoots return in spring.

What kohleria 'dark velvet''s hardiness rating actually means

Kohleria 'Dark Velvet' 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 10-11 (grown indoors in most US homes) — 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). Kohleria 'Dark Velvet' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Kohleria 'Dark Velvet' hardiness — frequently asked questions

Is kohleria 'dark velvet' cold hardy?

Kohleria 'Dark Velvet' 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. Kohleria 'Dark Velvet' can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (grown indoors in most US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature kohleria 'dark velvet' can survive?

What hardiness zone is kohleria 'dark velvet'?

Kohleria 'Dark Velvet' is rated USDA 10-11 (grown indoors in most US homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can kohleria 'dark velvet' 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 kohleria 'dark velvet' 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.