Cold hardiness & minimum temperature

Is Ivyleaf morning glory (Ipomoea hederacea)cold hardy? Hardiness zone & min temp

Also called Ivyleaf morning glory, Ivy-leaf morning glory.

More about ivyleaf morning glory

About Ivyleaf morning glory

Ipomoea hederacea · also called Ivyleaf morning glory, Ivy-leaf morning glory · flowering

Ivyleaf morning glory is a vigorous warm-season annual climber with distinctive three-lobed, ivy-shaped leaves and sky-blue to purple funnel flowers that open in the morning. Thrives in full sun and tolerates poor soils, making it easy to establish. Seeds are toxic to pets and humans. Considered a noxious agricultural weed in some US states.

Cold limit: USDA 2-11 · RHS H1b (18–35°C)

What ivyleaf morning glory's hardiness rating actually means

Ivyleaf morning glory 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 2-11 — 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). Ivyleaf morning glory has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

Ivyleaf morning glory hardiness — frequently asked questions

Is ivyleaf morning glory cold hardy?

Ivyleaf morning glory 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. Ivyleaf morning glory can only live outside year-round in genuinely frost-free climates (roughly USDA 2-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature ivyleaf morning glory can survive?

What hardiness zone is ivyleaf morning glory?

Ivyleaf morning glory is rated USDA 2-11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can ivyleaf morning glory 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 ivyleaf morning glory 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.