Cold hardiness & minimum temperature

Is Johnny Jump Up (Viola tricolor)cold hardy? Hardiness zone & min temp

Also called Johnny-Jump-Up, Wild Pansy, Heartsease, Love-in-Idleness.

More about johnny jump up

About Johnny Jump Up

Viola tricolor · also called Johnny-Jump-Up, Wild Pansy · flowering

A charming cool-season annual or short-lived perennial bearing small tricolour flowers in purple, yellow, and white with a distinctive dark face. Reaches 10–20 cm. Freely self-seeds, naturalising in borders and lawns. Viola tricolor is listed by ASPCA as mildly toxic to cats and dogs due to saponins.

Cold limit: USDA 3–8 (cool-season annual or self-seeding biennial) · RHS H5 (hardy to around -15°C) (5–18°C)

What johnny jump up's hardiness rating actually means

Hardiness works differently for johnny jump up: 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 H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 3–8 (cool-season annual or self-seeding biennial) — 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 johnny jump up 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 johnny jump up 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 johnny jump up can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Frost protection for borderline johnny jump up

Johnny Jump Up 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.

Johnny Jump Up hardiness — frequently asked questions

Is johnny jump up cold hardy?

Hardiness works differently for johnny jump up: 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. Johnny Jump Up is grown 3–8 (cool-season annual or self-seeding biennial); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature johnny jump up 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 johnny jump up?

Johnny Jump Up is rated USDA 3–8 (cool-season annual or self-seeding biennial) and RHS H5 — Hardy in most of the UK and in cold winters.

Can johnny jump up 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 johnny jump up 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.