Hardiness Zones

The USDA uses a "hardiness zone" system to describe how well a plant will survive winter. The zones run from the coldest and harshest zone 1 to a frost-free zone 11. For comparison, Fairbanks, Alaska is zone 1, and International Falls, Minnesota is zone 3, while the southernmost reaches of the Continental US is zone 10.

Here in Colorado, we do have some areas that are zone 3, but our Front Range region generally varies from zone 4 to zone 5. Surprisingly, the further east you go in the Denver area, the more harsh the climate becomes. Parker is a pretty solid zone 4, while the area along the Platt River is generally a zone 5. In general, the reason for the zone 4 areas has more to do with how early in the fall and late in the spring we can get bad weather than with the lowest temperature that we can expect.

I can't tell you how many customers have been convinced that we live in an area where you can grow Rhododendrons, Azaleas, Dogwood trees, and Japanese Maple. There are always folks who will sell a person whatever it is that they want to believe, but these beautiful plants are simply not reliable in a zone 5, let alone a zone 4 climate.

Bottom line - steer clear of anything that requires zone 6 or above, and be cautious of zone 5 plants - depending on exactly where you live.

Here is a link to help you determine your exact zone, as well as a way to look-up plants appropriate to your zone:

USDA Hardiness Zones