Cold hardiness & minimum temperature

Is Red Kohleria (Kohleria eriantha)cold hardy? Hardiness zone & min temp

Also called Red Kohleria, Woolly Kohleria, Tree Gloxinia.

More about red kohleria

About Red Kohleria

Kohleria eriantha · also called Red Kohleria, Woolly Kohleria · tropical

Kohleria eriantha is a rhizomatous perennial in the Gesneriaceae family, native to Colombia, producing erect, velvety stems and brilliant orange-red tubular flowers spotted with yellow on the lower lobes. It thrives as a houseplant or conservatory specimen in bright filtered light with high humidity, and its underground rhizomes allow it to survive periods of dryness and facilitate easy propagation. The most important care fact is to never splash water on the densely hairy leaves, which trap moisture and develop rot patches or botrytis. Kohleria is not individually listed by the ASPCA; treat with caution around pets.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1c (16–24°C)

Watch for — Rhizome rot from overwatering: Overwatering, especially in winter when the plant is semi-dormant, causes the rhizomes to blacken and decay; always let the top of the compost dry slightly before watering and ensure the pot has drainage holes that are not blocked.

What red kohleria's hardiness rating actually means

Red Kohleria 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-12 (indoor in most climates) — 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 5 °C (and never frost). Red Kohleria has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for red kohleria as it gets too cold:

Below about about 5 °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 red kohleria go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 red kohleria can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Red Kohleria hardiness — frequently asked questions

Is red kohleria cold hardy?

Red Kohleria 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. Red Kohleria can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature red kohleria can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Red Kohleria has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is red kohleria?

Red Kohleria is rated USDA 10-12 (indoor in most climates) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can red kohleria survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 red kohleria below its minimum temperature?

Below about about 5 °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.