Cold hardiness & minimum temperature

Is Houttuynia cordata (Houttuynia cordata)cold hardy? Hardiness zone & min temp

Also called Chameleon Plant, Fish Mint, Rainbow Plant.

More about houttuynia cordata

About Houttuynia cordata

Houttuynia cordata · also called Chameleon Plant, Fish Mint · flowering

Houttuynia cordata is a vigorous, spreading marginal perennial grown for heart-shaped leaves that smell of orange or coriander when crushed and small white-bracted summer flowers. It thrives in wet soil or shallow water at pond edges. Beautiful but notoriously invasive via running rhizomes, so most growers confine it to a pot or sunken container.

Cold limit: USDA 5-11 (root-hardy outdoors, dies back in winter) · RHS H5 (15-26°C)

Watch for — Winter dieback confusion: Top growth collapses entirely in autumn, which can look like death. The rhizomes are hardy and reshoot in late spring; mark the position and keep the soil moist over winter.

What houttuynia cordata's hardiness rating actually means

Yes — houttuynia cordata is genuinely cold hardy. Rated RHS H5 and USDA 5-11 (root-hardy outdoors, dies back in winter), 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 5-11 (root-hardy outdoors, dies back in winter) — 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. Houttuynia cordata is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for houttuynia cordata 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 houttuynia cordata go outside or overwinter — and where?

Plant it out within USDA 5-11 (root-hardy outdoors, dies back in winter) 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 houttuynia cordata can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Houttuynia cordata hardiness — frequently asked questions

Is houttuynia cordata cold hardy?

Yes — houttuynia cordata is genuinely cold hardy. Rated RHS H5 and USDA 5-11 (root-hardy outdoors, dies back in winter), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Houttuynia cordata is hardy across USDA 5-11 (root-hardy outdoors, dies back in winter); 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 houttuynia cordata can survive?

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

What hardiness zone is houttuynia cordata?

Houttuynia cordata is rated USDA 5-11 (root-hardy outdoors, dies back in winter) and RHS H5 — Hardy in most of the UK and in cold winters.

Can houttuynia cordata survive winter outside?

Plant it out within USDA 5-11 (root-hardy outdoors, dies back in winter) 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 houttuynia cordata 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.