What is a Hardiness Zone?
Knowing the Hardiness of a Species gives you an Indication on the Probability that a Plant of this Species will survive the Winter Outdoors, without protection, in your Geographic Area
You will find the USDA Hardiness Index for each Plant Species in the Header of the "Description" Section, in each Product Sheet of the Catalog
The USDA Hardiness Index shows in the format Z$, with:
- Z = USDA Zone (hardiness)
- $ = Numeric value of the USDA Hardiness Scale, from 0 to 14
(referring to the Average Winter Temperature, from the coldest to warmest)
To find out what Average Winter Temperature corresponds to a Z Index, refer to this Table:
To find out the Z Index for your Geographic Area, refer to these Maps:
Interactive map of other Countries
How to Use the Z Index? Examples
A Plant Species has a Hardiness Index of Z8
My Geographic Area is Z6
It is therefore unlikely that this Species will survive the Winter without protection in my Garden
A Plant Species has a Hardiness Index of Z7 and I live in Z7 or Z8
Perfect
A Plant Species has a Hardiness Index of Z6 and I live in Z11
This plant will survive the Winter in my garden without protection
In practice, it may not survive to summer
(species unadapted to the local climate conditions)