What is the hardiness System?

(here is another link to a good hardiness zone site)

When it is said that a plant is rated to Zone 6, it means it will usually not endure the winter below -10°F (-23°C). Occasionally, you'll read that a plant is rated between two zones (e.g., Zone 5 to 9). By that is meant that the plant can survive to -20°F (-29°C) in winter, but the summer temperatures found in Zone 9 will be too warm for the plant to live.

Sometimes you'll see an additional modification of the 10°F divisions. That is, the divisions are in 5° increments such as Zone 7a or 7b. When related with the same numbered zone, the "b increment" is always the warmest. Therefore, Zone 7a means the average lowest winter temperature is 0° to 5°F (-18° to -15°C), and Zone 7b is 5° to 10°F (-15° to -12°C).

Hardiness Zone Table

Hardiness
Zone

Avg. Min. Temp.
(°F)

Avg. Min. Temp
(°C)

1
2a
2b
3a
3b
4a
4b
5a
5b
6a
6b
7a
7b
8a
8b
9a
9b
10a
10b
11

below -50°
-45°
-40°
-35°
-30°
-25°
-20°
-15°
-10°
-5°
0°
5°
10°
15°
20°
25°
30°
35°
40°
above 45°

below -46°
-43°
-40°
-37°
-34°
-31°
-29°
-26°
-23°
-20°
-18°
-15°
-12°
-9°
-7°
-4°
-1°
2°
4°
above 7°

Some examples of coniferous trees’ hardiness zones from the trees listed on the descriptions page are:

EASTERN HEMLOCK=3-8

MAIDENHAIR TREE=5

MOUNTAIN PINE=3

DEODAR=7b

LAWSON CYPRESS=6b

WESTERN RED CEDAR=3

HINOKI CYPRESS=4-8

LEYLAND CYPRESS=7

COLORADO SPRUCE=3a

USA Map of hardiness zones-to link to

If you want to get a tree make sure that it will live well where you live, to do so, go here!