Cold hardiness & minimum temperature

Is Snapdragon vine (Maurandya barclayana)cold hardy? Hardiness zone & min temp

Also called Snapdragon vine, Mexican viper, Climbing snapdragon, Chickabiddy vine.

More about snapdragon vine

About Snapdragon vine

Maurandya barclayana · also called Snapdragon vine, Mexican viper · flowering

Snapdragon vine is an elegant twining climber from Mexico, bearing tubular trumpet flowers in white, pink, or deep purple through summer and autumn. It grows quickly to 4 m, making it ideal for covering trellises, fences, and arches. In cool climates it is grown as a half-hardy annual; in mild frost-free gardens it behaves as a perennial. ASPCA lists the genus Maurandya as non-toxic.

Cold limit: USDA 9–11 (grown as annual in zones 3–8) · RHS H2 (10–24°C)

Watch for — Slow to start after transplanting: Seeds are slow to germinate and seedlings can stall in cold compost; bottom heat of 18–21°C dramatically improves germination speed and early vigour.

What snapdragon vine's hardiness rating actually means

Hardiness works differently for snapdragon vine: 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 9–11 (grown as annual in zones 3–8) — 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 snapdragon vine 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 snapdragon vine 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 snapdragon vine 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 snapdragon vine

Snapdragon vine 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.

Snapdragon vine hardiness — frequently asked questions

Is snapdragon vine cold hardy?

Hardiness works differently for snapdragon vine: 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. Snapdragon vine is grown 9–11 (grown as annual in zones 3–8); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature snapdragon vine 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 snapdragon vine?

Snapdragon vine is rated USDA 9–11 (grown as annual in zones 3–8) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can snapdragon vine 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 snapdragon vine 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.