Cold hardiness & minimum temperature

Is Miniature Creeping Jenny (Lysimachia japonica 'Minutissima')cold hardy? Hardiness zone & min temp

Also called Miniature Creeping Jenny, Japanese Creeping Jenny Minutissima.

More about miniature creeping jenny

About Miniature Creeping Jenny

Lysimachia japonica 'Minutissima' · also called Miniature Creeping Jenny, Japanese Creeping Jenny Minutissima · flowering

Miniature Creeping Jenny is a tiny, mat-forming ground cover with delicate, rounded chartreuse leaves and small yellow flowers in summer. Perfect for alpine troughs, the edges of containers, terrariums, and between paving stones, it forms a dense, low carpet. Requires consistent moisture and partial shade to prevent leaf scorch.

Cold limit: USDA 6-9 · RHS H5 (−10°C to 25°C)

What miniature creeping jenny's hardiness rating actually means

Yes — miniature creeping jenny is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 6-9 — 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 about −15 to −10 °C. Miniature Creeping Jenny is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for miniature creeping jenny as it gets too cold:

It tolerates winter lows to about −15 to −10 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can miniature creeping jenny go outside or overwinter — and where?

Plant it out within USDA 6-9 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

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 miniature creeping jenny can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Miniature Creeping Jenny hardiness — frequently asked questions

Is miniature creeping jenny cold hardy?

Yes — miniature creeping jenny is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Miniature Creeping Jenny is hardy across USDA 6-9; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature miniature creeping jenny can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Miniature Creeping Jenny is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is miniature creeping jenny?

Miniature Creeping Jenny is rated USDA 6-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can miniature creeping jenny survive winter outside?

Plant it out within USDA 6-9 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to miniature creeping jenny below its minimum temperature?

It tolerates winter lows to about −15 to −10 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.