Cold hardiness & minimum temperature

Is Prince of Wales Juniper (Juniperus horizontalis 'Prince of Wales')cold hardy? Hardiness zone & min temp

Also called Prince of Wales Juniper, Creeping Juniper.

More about prince of wales juniper

About Prince of Wales Juniper

Juniperus horizontalis 'Prince of Wales' · also called Prince of Wales Juniper, Creeping Juniper · flowering

Prince of Wales Juniper is a tough, low creeping conifer forming a dense blue-green carpet about 15 cm tall and 1.5-2 m wide, often flushing plum-purple in winter cold. A prairie-bred selection, it excels as drought-tolerant ground cover on banks and in rock gardens, asking only full sun and sharply drained soil.

Cold limit: USDA 3-9 (very cold-hardy prairie selection) · RHS H7 (-40 to 35°C)

Watch for — Thinning in shade: Insufficient sun produces a sparse, patchy mat and weaker winter colour; site in full sun.

What prince of wales juniper's hardiness rating actually means

Yes — prince of wales juniper is genuinely cold hardy. Rated RHS H7 and USDA 3-9 (very cold-hardy prairie selection), 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 3-9 (very cold-hardy prairie selection) — 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. Prince of Wales Juniper is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for prince of wales juniper 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 prince of wales juniper go outside or overwinter — and where?

Plant it out within USDA 3-9 (very cold-hardy prairie selection) 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 prince of wales juniper can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Prince of Wales Juniper hardiness — frequently asked questions

Is prince of wales juniper cold hardy?

Yes — prince of wales juniper is genuinely cold hardy. Rated RHS H7 and USDA 3-9 (very cold-hardy prairie selection), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Prince of Wales Juniper is hardy across USDA 3-9 (very cold-hardy prairie selection); 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 prince of wales juniper can survive?

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

What hardiness zone is prince of wales juniper?

Prince of Wales Juniper is rated USDA 3-9 (very cold-hardy prairie selection) and RHS H7 — Hardy in the severest European continental winters.

Can prince of wales juniper survive winter outside?

Plant it out within USDA 3-9 (very cold-hardy prairie selection) 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 prince of wales juniper 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.