Cold hardiness & minimum temperature

Is Beach Cabbage (Scaevola taccada)cold hardy? Hardiness zone & min temp

Also called Beach Cabbage, Beach Naupaka, Sea Lettuce, Half Flower.

More about beach cabbage

About Beach Cabbage

Scaevola taccada · also called Beach Cabbage, Beach Naupaka · tropical

Scaevola taccada is a fast-growing, evergreen tropical shrub widespread across the Indo-Pacific coastline from East Africa to Polynesia, recognised by its somewhat succulent, spoon-shaped leaves and distinctive fan-shaped white flowers that appear as if split in half. It thrives in full sun with sandy, well-drained soil and is extremely tolerant of salt spray, coastal winds, and drought once established, making it an outstanding choice for tropical coastal landscaping and dune stabilisation. The critical care point is to provide excellent drainage, as the plant is sensitive to waterlogged conditions despite its coastal tolerance. Not listed as toxic by major veterinary databases.

Cold limit: USDA 10-12 · RHS H1a (15–35°C)

What beach cabbage's hardiness rating actually means

Beach Cabbage 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 10-12 — 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 above about 15 °C (warm, never cold). Beach Cabbage has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for beach cabbage as it gets too cold:

Below about above about 15 °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 beach cabbage go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 beach cabbage can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Beach Cabbage hardiness — frequently asked questions

Is beach cabbage cold hardy?

Beach Cabbage 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. Beach Cabbage can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature beach cabbage can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Beach Cabbage has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is beach cabbage?

Beach Cabbage is rated USDA 10-12 and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can beach cabbage survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 beach cabbage below its minimum temperature?

Below about above about 15 °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.