Cold hardiness & minimum temperature

Is Chrysanthemum 'Mei-kyo' (Chrysanthemum 'Mei-kyo')cold hardy? Hardiness zone & min temp

Also called Mei-kyo Chrysanthemum, Mei Kyo Mum, Japanese Garden Mum.

More about chrysanthemum 'mei-kyo'

About Chrysanthemum 'Mei-kyo'

Chrysanthemum 'Mei-kyo' · also called Mei-kyo Chrysanthemum, Mei Kyo Mum · flowering

Chrysanthemum 'Mei-kyo' is a compact, traditional Japanese-heritage garden mum producing masses of small, double, rose-pink to mauve pompon flowers from mid-autumn onward. Hardy and long-lived, it is considered one of the finest autumn border plants. Toxic to dogs, cats, and horses.

Cold limit: USDA 4-9 · RHS H6 (5-20°C)

Watch for — Crown rot in heavy soils: The main winter threat; ensure good drainage and avoid planting in frost pockets where moisture accumulates.

What chrysanthemum 'mei-kyo''s hardiness rating actually means

Yes — chrysanthemum 'mei-kyo' is genuinely cold hardy. Rated RHS H6 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA 4-9 — 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 −20 to −15 °C. Chrysanthemum 'Mei-kyo' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for chrysanthemum 'mei-kyo' as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 chrysanthemum 'mei-kyo' go outside or overwinter — and where?

Plant it out within USDA 4-9 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 chrysanthemum 'mei-kyo' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Chrysanthemum 'Mei-kyo' hardiness — frequently asked questions

Is chrysanthemum 'mei-kyo' cold hardy?

Yes — chrysanthemum 'mei-kyo' is genuinely cold hardy. Rated RHS H6 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Chrysanthemum 'Mei-kyo' is hardy across USDA 4-9; 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 chrysanthemum 'mei-kyo' can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Chrysanthemum 'Mei-kyo' is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is chrysanthemum 'mei-kyo'?

Chrysanthemum 'Mei-kyo' is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can chrysanthemum 'mei-kyo' survive winter outside?

Plant it out within USDA 4-9 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 chrysanthemum 'mei-kyo' below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.