Cold hardiness & minimum temperature

Is Tessellated Colchicum (Colchicum agrippinum)cold hardy? Hardiness zone & min temp

Also called Tessellated colchicum, Chequered autumn crocus, Tessellated meadow saffron.

More about tessellated colchicum

About Tessellated Colchicum

Colchicum agrippinum · also called Tessellated colchicum, Chequered autumn crocus · flowering

Colchicum agrippinum is a compact corm-forming perennial native to the eastern Mediterranean, producing distinctive pink-purple, strongly tessellated (chequered) flowers in late summer and early autumn — well before its strap-like leaves emerge the following spring. Plant the corms in free-draining soil in a sunny spot and leave them undisturbed; they naturalise readily in gravel gardens or the front of a border. Keep reliably dry during summer dormancy to mimic their natural Mediterranean bake. All parts of this plant are highly toxic to cats and dogs due to colchicine.

Cold limit: USDA 4-9 · RHS H6 (-15 to 25 °C)

Watch for — Corm rot: Caused by Fusarium or excess winter moisture; ensure sharp drainage and avoid planting in low-lying areas or heavy clay where water pools around the corm.

What tessellated colchicum's hardiness rating actually means

Yes — tessellated colchicum 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. Tessellated Colchicum is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for tessellated colchicum 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 tessellated colchicum 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 tessellated colchicum can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Tessellated Colchicum hardiness — frequently asked questions

Is tessellated colchicum cold hardy?

Yes — tessellated colchicum 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. Tessellated Colchicum 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 tessellated colchicum can survive?

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

What hardiness zone is tessellated colchicum?

Tessellated Colchicum is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can tessellated colchicum 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 tessellated colchicum 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.