The USDA Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which perennial plants are most likely to thrive at a location. The map is based on the average annual extreme minimum winter temperature, displayed as 10-degree F zones and 5-degree F half zones. The temperatures given doesn’t mean that it can’t get colder than expected. It is just an average of the last 30-50 years of compiled information to be used as a guideline.

The Plant Hardiness Zone Map, provided by the United States Department of Agriculture (USDA), serves as an invaluable tool for gardeners, landscapers, and farmers across the nation. It offers a standard reference to understand the climatic conditions ideal for growing specific plants, ensuring healthier landscapes and thriving gardens. This map helps with planning and success when planning and planting perennials, trees and shrubs. 

In 2023, the USDA hardiness zone map was revised at that time to show the new climates that have resulted over the past few decades due to a warming trend. Understanding your planting zone in Colorado will increase your ability to create a garden that can flourish from year to year. Planting vegetables, trees, flowers, and other plants that are appropriate for your zone will make your gardening less frustrating.

When shopping for plants, look at the back of the tag and find the zone hardiness for that plant. The lower the zone, the colder the region it can grow in. Picking a plant that is zoned for your region gives you the best chance for that plant to survive the winters. The best chance is not a guarantee. Other things that could affect your plants survival are summer temperature, moisture and humidity, and micro climates.  When in doubt pick out plants that are native or varieties of natives. This will ensure that the plants you choose has a good chance to survive that area if the area chosen has the same moisture and sun requirements that they need. If at all possible, pick plants that are a zone colder to increase the odds. 

Now that they have changed our zone to zone 6a, don’t go out and buy a bunch for that zone before doing your research and expect them to live. Remember that we live in a high desert. The high desert gives you cold winds, lack of humidity and temperature swings that zone hardiness doesn’t account for. 

As the USDA Plant Hardiness Zone Map evolves to reflect changing climates, gardeners must stay informed and adapt their strategies accordingly. The key to successful gardening lies not just in understanding your zone but also in considering additional factors that influence plant health. By being mindful of these changes and making informed choices, gardeners can continue to cultivate vibrant, resilient landscapes in the face of a shifting climate.