Cold hardiness & minimum temperature

Is Ipomoea batatas 'Blackie' (Ipomoea batatas 'Blackie')cold hardy? Hardiness zone & min temp

Also called Blackie sweet potato vine, ornamental sweet potato.

More about ipomoea batatas 'blackie'

About Ipomoea batatas 'Blackie'

Ipomoea batatas 'Blackie' · also called Blackie sweet potato vine, ornamental sweet potato · flowering

'Blackie' is an ornamental sweet potato vine grown for its deep purple-black, maple-like lobed foliage rather than flowers. A vigorous, trailing tender perennial usually treated as an annual, it spills dramatically from containers and hanging baskets and races along the ground as bedding. Rarely blooms in cultivation; its value is the bold, near-black cascading leaves that contrast with brighter plants.

Cold limit: USDA 9-11 (tender perennial; grown as an annual in colder zones) · RHS H1c (18 to 32°C)

Watch for — Tuber rot in cold or wet soil: Tubers rot in cold, waterlogged conditions. Lift and store tubers frost-free over winter, or take cuttings, in zones below 9.

What ipomoea batatas 'blackie''s hardiness rating actually means

Hardiness works differently for ipomoea batatas 'blackie': 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 9-11 (tender perennial; grown as an annual in colder 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

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 ipomoea batatas 'blackie' 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 ipomoea batatas 'blackie' 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 ipomoea batatas 'blackie' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Frost protection for borderline ipomoea batatas 'blackie'

Ipomoea batatas 'Blackie' 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.

Ipomoea batatas 'Blackie' hardiness — frequently asked questions

Is ipomoea batatas 'blackie' cold hardy?

Hardiness works differently for ipomoea batatas 'blackie': 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. Ipomoea batatas 'Blackie' is grown 9-11 (tender perennial; grown as an annual in colder zones); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature ipomoea batatas 'blackie' 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 ipomoea batatas 'blackie'?

Ipomoea batatas 'Blackie' is rated USDA 9-11 (tender perennial; grown as an annual in colder zones) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can ipomoea batatas 'blackie' 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 ipomoea batatas 'blackie' 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.