Cold hardiness & minimum temperature

Is Degroot's Spire Arborvitae (Thuja occidentalis 'Degroot's Spire')cold hardy? Hardiness zone & min temp

Also called Degroot's Spire, Columnar Arborvitae.

More about degroot's spire arborvitae

About Degroot's Spire Arborvitae

Thuja occidentalis 'Degroot's Spire' · also called Degroot's Spire, Columnar Arborvitae · flowering

An exceptionally slim, spire-like evergreen with tightly twisted, dark green foliage sprays that give it distinctive texture. Its extremely narrow profile suits tight spaces, vertical accents, and slender screens where wider arborvitae won't fit. It prefers full sun and consistently moist, well-drained soil, holds its form without shearing, and is reliably cold-hardy.

Cold limit: USDA 3-8 (very narrow columnar) · RHS H7 (-37 to 30°C)

Watch for — Winter browning: Drying winter winds can bleach foliage; water well before freeze-up and shelter exposed plantings.

What degroot's spire arborvitae's hardiness rating actually means

Yes — degroot's spire arborvitae is genuinely cold hardy. Rated RHS H7 and USDA 3-8 (very narrow columnar), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 3-8 (very narrow columnar) — 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 below about −20 °C. Degroot's Spire Arborvitae is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for degroot's spire arborvitae as it gets too cold:

It tolerates winter lows to about −20 °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 degroot's spire arborvitae go outside or overwinter — and where?

Plant it out within USDA 3-8 (very narrow columnar) 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 degroot's spire arborvitae can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Degroot's Spire Arborvitae hardiness — frequently asked questions

Is degroot's spire arborvitae cold hardy?

Yes — degroot's spire arborvitae is genuinely cold hardy. Rated RHS H7 and USDA 3-8 (very narrow columnar), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Degroot's Spire Arborvitae is hardy across USDA 3-8 (very narrow columnar); 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 degroot's spire arborvitae can survive?

Minimum survivable temperature is roughly below about −20 °C. Degroot's Spire Arborvitae is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is degroot's spire arborvitae?

Degroot's Spire Arborvitae is rated USDA 3-8 (very narrow columnar) and RHS H7 — Hardy in the severest European continental winters.

Can degroot's spire arborvitae survive winter outside?

Plant it out within USDA 3-8 (very narrow columnar) 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 degroot's spire arborvitae below its minimum temperature?

It tolerates winter lows to about −20 °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.