Cold hardiness & minimum temperature

Is Burr Oak (Quercus macrocarpa)cold hardy? Hardiness zone & min temp

Also called burr oak, bur oak, mossycup oak.

More about burr oak

About Burr Oak

Quercus macrocarpa · also called burr oak, bur oak · edible

Burr oak is a massive, rugged North American white-oak with corky branches and the largest acorns of any native oak, fringed by mossy cup caps. The sweet, low-tannin acorns are edible to humans after leaching. Exceptionally adaptable and drought- and cold-hardy, it is a slow-growing, very long-lived prairie and savanna tree for large landscapes.

Cold limit: USDA 3-8 (very cold-hardy outdoor tree) · RHS H7 (-40 to 35°C)

What burr oak's hardiness rating actually means

Yes — burr oak is genuinely cold hardy. Rated RHS H7 and USDA 3-8 (very cold-hardy outdoor tree), 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 cold-hardy outdoor tree) — 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. Burr Oak is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for burr oak 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 burr oak go outside or overwinter — and where?

Plant it out within USDA 3-8 (very cold-hardy outdoor tree) 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 burr oak can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Burr Oak hardiness — frequently asked questions

Is burr oak cold hardy?

Yes — burr oak is genuinely cold hardy. Rated RHS H7 and USDA 3-8 (very cold-hardy outdoor tree), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Burr Oak is hardy across USDA 3-8 (very cold-hardy outdoor tree); 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 burr oak can survive?

Minimum survivable temperature is roughly below about −20 °C. Burr Oak is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is burr oak?

Burr Oak is rated USDA 3-8 (very cold-hardy outdoor tree) and RHS H7 — Hardy in the severest European continental winters.

Can burr oak survive winter outside?

Plant it out within USDA 3-8 (very cold-hardy outdoor tree) 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 burr oak 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.