Cold hardiness & minimum temperature

Is Scaevola aemula 'Bombay Dark Blue' (Scaevola aemula 'Bombay Dark Blue')cold hardy? Hardiness zone & min temp

Also called Bombay Dark Blue Fan Flower, Dark Blue Scaevola.

More about scaevola aemula 'bombay dark blue'

About Scaevola aemula 'Bombay Dark Blue'

Scaevola aemula 'Bombay Dark Blue' · also called Bombay Dark Blue Fan Flower, Dark Blue Scaevola · flowering

'Bombay Dark Blue' is a compact fan flower bred for masses of fan-shaped, deep blue-purple blooms on a tidy, well-branched habit. This Australian-native warm-season annual is heat- and drought-tolerant, blooms tirelessly without deadheading, and is a favourite for containers, baskets and edging where it draws bees through summer into autumn.

Cold limit: USDA 10-11 (perennial in frost-free zones; grown as an annual elsewhere) · RHS H2 (18-29°C)

Watch for — Frost damage: Frost kills the plant where it cannot overwinter; treat as a tender annual outside frost-free zones.

What scaevola aemula 'bombay dark blue''s hardiness rating actually means

Hardiness works differently for scaevola aemula 'bombay dark blue': it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". 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 10-11 (perennial in frost-free zones; grown as an annual 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

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

Concretely, for scaevola aemula 'bombay dark blue' as it gets too cold:

Light frost (around 0 to −2 °C) damages or kills tender summer crops outright; cold-hardy types take a few degrees of frost.
The plant does not "survive winter" — its life cycle simply ends, by design, when frost arrives or it finishes cropping.
A surprise late spring frost can also kill young transplants set out too early, before the season even starts.

Can scaevola aemula 'bombay dark blue' go outside or overwinter — and where?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost.
In short-season zones, start it indoors or under cover to stretch the effective growing window.
Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

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 scaevola aemula 'bombay dark blue' 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 scaevola aemula 'bombay dark blue'

Scaevola aemula 'Bombay Dark Blue' is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks.
Have row cover ready for an unexpected late spring or early autumn frost.
Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.

Scaevola aemula 'Bombay Dark Blue' hardiness — frequently asked questions

Is scaevola aemula 'bombay dark blue' cold hardy?

Hardiness works differently for scaevola aemula 'bombay dark blue': it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". A seasonal crop, not a perennial. Scaevola aemula 'Bombay Dark Blue' is grown 10-11 (perennial in frost-free zones; grown as an annual elsewhere); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature scaevola aemula 'bombay dark blue' can survive?

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

What hardiness zone is scaevola aemula 'bombay dark blue'?

Scaevola aemula 'Bombay Dark Blue' is rated USDA 10-11 (perennial in frost-free zones; grown as an annual elsewhere) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can scaevola aemula 'bombay dark blue' survive winter outside?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost. In short-season zones, start it indoors or under cover to stretch the effective growing window. Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

How do I protect scaevola aemula 'bombay dark blue' from frost?

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks. Have row cover ready for an unexpected late spring or early autumn frost. Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.