Cold hardiness & minimum temperature

Is Pelargonium 'Wilhelm Langguth' (Pelargonium 'Wilhelm Langguth')cold hardy? Hardiness zone & min temp

Also called Wilhelm Langguth geranium, Silver-leaved pelargonium.

More about pelargonium 'wilhelm langguth'

About Pelargonium 'Wilhelm Langguth'

Pelargonium 'Wilhelm Langguth' · also called Wilhelm Langguth geranium, Silver-leaved pelargonium · flowering

A silver-variegated zonal pelargonium with grey-green leaves boldly edged in creamy white, topped by clusters of cherry-red single flowers. Vigorous and old-fashioned, it earns its keep as a bedding and container plant for the brightness of its foliage. Tender, it needs full sun, sharp drainage and frost-free winter quarters to thrive.

Cold limit: USDA 9-11 (tender; lift or overwinter under cover where frost occurs) · RHS H1c (10-24°C)

What pelargonium 'wilhelm langguth''s hardiness rating actually means

Pelargonium 'Wilhelm Langguth' 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 9-11 (tender; lift or overwinter under cover where frost occurs) — 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). Pelargonium 'Wilhelm Langguth' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for pelargonium 'wilhelm langguth' 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 pelargonium 'wilhelm langguth' 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 pelargonium 'wilhelm langguth' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Pelargonium 'Wilhelm Langguth' hardiness — frequently asked questions

Is pelargonium 'wilhelm langguth' cold hardy?

Pelargonium 'Wilhelm Langguth' 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. Pelargonium 'Wilhelm Langguth' can only live outside year-round in genuinely frost-free climates (roughly USDA 9-11 (tender; lift or overwinter under cover where frost occurs)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature pelargonium 'wilhelm langguth' can survive?

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

What hardiness zone is pelargonium 'wilhelm langguth'?

Pelargonium 'Wilhelm Langguth' is rated USDA 9-11 (tender; lift or overwinter under cover where frost occurs) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can pelargonium 'wilhelm langguth' 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 pelargonium 'wilhelm langguth' 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.