Cold hardiness & minimum temperature

Is Heart-leaved Globe Daisy (Globularia cordifolia)cold hardy? Hardiness zone & min temp

Also called Heart-leaved Globe Daisy, Matted Globe Daisy.

More about heart-leaved globe daisy

About Heart-leaved Globe Daisy

Globularia cordifolia · also called Heart-leaved Globe Daisy, Matted Globe Daisy · flowering

Heart-leaved Globe Daisy is a compact, evergreen sub-shrub native to rocky limestone outcrops in southern Europe and the Alps. It forms tight, dark-green mats studded with small blue-lilac globe-shaped flower heads in late spring and early summer. Ideal for rock gardens, walls, and alpine troughs in well-drained, alkaline conditions.

Cold limit: USDA 5-8 · RHS H6 (-20°C to 22°C)

Watch for — Winter wet rot: Prolonged moisture on or around the crown in cold wet winters causes rot and can kill the entire mat. Ensure excellent drainage; in containers, tilt the pot slightly to aid run-off and shelter from persistent winter rain.

What heart-leaved globe daisy's hardiness rating actually means

Yes — heart-leaved globe daisy is genuinely cold hardy. Rated RHS H6 and USDA 5-8, 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 5-8 — 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. Heart-leaved Globe Daisy is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for heart-leaved globe daisy 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 heart-leaved globe daisy go outside or overwinter — and where?

Plant it out within USDA 5-8 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 heart-leaved globe daisy can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Heart-leaved Globe Daisy hardiness — frequently asked questions

Is heart-leaved globe daisy cold hardy?

Yes — heart-leaved globe daisy is genuinely cold hardy. Rated RHS H6 and USDA 5-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Heart-leaved Globe Daisy is hardy across USDA 5-8; 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 heart-leaved globe daisy can survive?

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

What hardiness zone is heart-leaved globe daisy?

Heart-leaved Globe Daisy is rated USDA 5-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can heart-leaved globe daisy survive winter outside?

Plant it out within USDA 5-8 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 heart-leaved globe daisy 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.