Cold hardiness & minimum temperature

Is Tropaeolum majus 'Jewel of Africa' (Tropaeolum majus 'Jewel of Africa')cold hardy? Hardiness zone & min temp

Also called Jewel of Africa Nasturtium, Variegated Nasturtium.

More about tropaeolum majus 'jewel of africa'

About Tropaeolum majus 'Jewel of Africa'

Tropaeolum majus 'Jewel of Africa' · also called Jewel of Africa Nasturtium, Variegated Nasturtium · flowering

'Jewel of Africa' is a climbing, variegated nasturtium with cream-marbled foliage and a mix of yellow, red, cream and peach trumpet flowers. Vigorous and easy, this fast-growing annual scrambles up supports or trails from containers. Both flowers and peppery leaves are edible. It thrives on neglect and poor soil, flowering best when not over-fed or overwatered.

Cold limit: USDA 9-11 (frost-tender annual; killed by frost in cooler zones) · RHS H2 (13-27°C)

Watch for — Frost damage: Tender to even light frost. Sow or plant out only after the last frost, and expect plants to collapse with the first autumn frost.

What tropaeolum majus 'jewel of africa''s hardiness rating actually means

Tropaeolum majus 'Jewel of Africa' is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Its RHS rating of H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 9-11 (frost-tender annual; killed by frost in cooler zones) — 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 1 to 5 °C — tolerates cold but no real frost. Tropaeolum majus 'Jewel of Africa' shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for tropaeolum majus 'jewel of africa' as it gets too cold:

Down to roughly about 1 to 5 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can tropaeolum majus 'jewel of africa' go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (frost-tender annual; killed by frost in cooler zones) or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

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 tropaeolum majus 'jewel of africa' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline tropaeolum majus 'jewel of africa'

Tropaeolum majus 'Jewel of Africa' is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Tropaeolum majus 'Jewel of Africa' hardiness — frequently asked questions

Is tropaeolum majus 'jewel of africa' cold hardy?

Tropaeolum majus 'Jewel of Africa' is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA 9-11 (frost-tender annual; killed by frost in cooler zones) (and sheltered UK gardens) tropaeolum majus 'jewel of africa' can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature tropaeolum majus 'jewel of africa' can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Tropaeolum majus 'Jewel of Africa' shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is tropaeolum majus 'jewel of africa'?

Tropaeolum majus 'Jewel of Africa' is rated USDA 9-11 (frost-tender annual; killed by frost in cooler zones) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can tropaeolum majus 'jewel of africa' survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (frost-tender annual; killed by frost in cooler zones) or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect tropaeolum majus 'jewel of africa' from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.