Cold hardiness & minimum temperature

Is Garlic Vine (Adenocalymma comosum)cold hardy? Hardiness zone & min temp

Also called Garlic Vine, Yellow Trumpet Vine.

More about garlic vine

About Garlic Vine

Adenocalymma comosum · also called Garlic Vine, Yellow Trumpet Vine · tropical

An evergreen South American climbing vine in the Bignoniaceae family, prized for its plume-like clusters of long tubular yellow-to-orange flowers in early spring. Crushed foliage releases a faint garlic scent. Grow in full sun to part shade with free-draining soil and trellis support. Hardy only in frost-free zones 9–10.

Cold limit: USDA 9-10 · RHS H1b (15–35°C; minimum 5°C)

Watch for — Cold damage: Frost or temperatures below 5°C cause leaf damage and dieback. Move container plants indoors before first frost and provide winter protection for garden specimens in borderline climates.

What garlic vine's hardiness rating actually means

Garlic Vine 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 9-10 — 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). Garlic Vine has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Garlic Vine hardiness — frequently asked questions

Is garlic vine cold hardy?

Garlic Vine 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. Garlic Vine can only live outside year-round in genuinely frost-free climates (roughly USDA 9-10); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature garlic vine can survive?

Minimum survivable temperature is roughly about 10 °C (sustained cold below this is damaging). Garlic Vine has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is garlic vine?

Garlic Vine is rated USDA 9-10 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can garlic vine 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 garlic vine 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.