Hardiness Zones
The hardiness zones of plants refer
to geologically-defined areas where plants, or categories
of plants, are capable of growing. These zones are determined
by climate, with the major factor simply being the temperature.
These zones have been adopted around the world, but
were originally developed by the United States Department
of Agriculture (USDA). When reading information about
plants, it is normally referred to
simply by 'zone'.
Simple Scale

Detailed Scale
0 |
|
1 |
a |
-48.3 |
-51.1 |
b |
-45.6 |
-53.9 |
|
2 |
a |
-42.8 |
-45.6 |
b |
-40 |
-42.8 |
|
3 |
a |
-37.2 |
-40 |
b |
-34.4 |
-37.2 |
|
4 |
a |
-31.7 |
-34.4 |
b |
-28.9 |
-31.7 |
|
5 |
a |
-26.1 |
-28.9 |
b |
-23.3 |
-26.1 |
|
6 |
a |
-20.6 |
-23.3 |
b |
-17.8 |
-20.6 |
|
7 |
|
8 |
|
9 |
|
10 |
|
11 |
|
12 |
|