Cold hardiness & minimum temperature

Is Aloe Castillon (Aloe castilloniae)cold hardy? Hardiness zone & min temp

Also called Castillon aloe.

More about aloe castillon

About Aloe Castillon

Aloe castilloniae · also called Castillon aloe · houseplant

Aloe castilloniae is a striking dwarf Madagascan aloe with stacked, recurved olive-to-reddish leaves densely covered in white bristly spines along the margins and keel. It forms low sprawling stems and prized branched coral-red flower clusters. A sought-after collector's species, it stays compact, loves heat and bright light, and needs scrupulously sharp drainage.

Cold limit: USDA 10-11 (indoor elsewhere) · RHS H1c (13-30°C)

Watch for — Cold, wet rot: Being from Madagascar it rots easily if cool and damp. Keep it warm and nearly dry through winter.

What aloe castillon's hardiness rating actually means

Aloe Castillon 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 10-11 (indoor elsewhere) — 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). Aloe Castillon has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Aloe Castillon hardiness — frequently asked questions

Is aloe castillon cold hardy?

Aloe Castillon 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. Aloe Castillon can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (indoor elsewhere)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature aloe castillon can survive?

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

What hardiness zone is aloe castillon?

Aloe Castillon is rated USDA 10-11 (indoor elsewhere) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can aloe castillon 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 aloe castillon 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.