Alphabetical Plant Listing

Hardiness Zones in the United Kingdom

Regional Gardening, Hardiness Zones, UK Climate


Be aware of the hardiness zone in your area before you decide to buy plants. Some plants might not survive over winter!

Based on the minimum ten-year average winter temperatures, plant hardiness zone maps have been progressively developed, first by the Department of Agriculture (USDA) for the United States and then more or less applied to the rest of the planet. The purpose of these hardiness zones is to identify how well plants will withstand the cold winter temperatures of these zones. But keep in mind that these maps are mostly guidelines as they do not factor in any potential micro climates, precipitation, humidity, summer heat tolerance, etc.

Selecting plants suited to the diverse English climate will be a key step to success. If you know your hardiness zone, find the best plants for your climate area. If you are not sure which hardiness zone you belong to, please check the map below.

Alternatively, discover plenty of exciting garden ideas for your geographic area.

Hardiness Zones in the United Kingdom

  • The United Kingdom lies in USDA Plant Hardiness Zones 6 through 9 with some variations across regions and seasons. It enjoys a temperate maritime climate characterized by cool winters and warm summers. Summers are cooler than those on the continent (not much higher than 32ºC in summer), but the winters are milder (not much lower than 0ºC in winter). Around the coasts, February is normally the coldest month, but inland there is little to choose between January and February as the coldest month.
  • The frost free growing season is fairly long with the last frost dates ranging from March to April and the first frost dates starting as early as October until the end of November.

Plant Hardiness: Royal Horticultural Society Ratings and USDA Ratings

RHS Rating Temperature Hardiness USDA Zones
H6 -4ºF to 5ºF
-20ºC to -15ºC
Hardy
Very cold winter
6,7
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H5 5ºF to 14ºF
-15ºC to -10ºC
Hardy
Cold winter
7,8
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H4 14ºF to 23ºF
-10ºC to -5ºC
Hardy
Average winter
8,9
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H3 23ºF to 24ºF
-5ºC to 1ºC
Half-hardy  9
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H2 34ºF to 41ºF
1ºC to 5ºC
Tender cool 10
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H1c 41ºF to 50ºF
5ºC to 10ºC
Warm temperate 11
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H1b 50ºF to 59ºF
10ºC to 15ºC
Subtropical 12
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H1a > 59ºF
  15ºC
Tropical 13
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Guide Information

Hardiness 6 - 9
United Kingdom Plant Combination Ideas United Kingdom Guides

Photo: 123rf

While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.

Guide Information

Hardiness 6 - 9
United Kingdom Plant Combination Ideas United Kingdom Guides

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