USDA Hardiness Map & Finding Your Zone

The USDA Plant Hardiness Zone Map (shown above) is a tool that can help you find the right plants for your yard. 

USDA zones are based on the average annual extreme minimum winter temperature. These zones provide a convenient way to communicate and compare the climates within the United States and Puerto Rico. 

Each color represents average coldest temperature in 10°F zones. Zones range from Zone 1 (coldest) to Zone 13 (warmest). 

• Refer to the map above at a glance
• For more specific detail, you can enter your zipcode into our Zone Filter (find it here)
• Or, click on the map above to enter your zipcode into the USDA Zone Filter

Did You Know? In late 2023, the USDA updated their Hardiness Zones based on 1991-2020 weather data - and they represent a trend in warming temperatures.

• USDA Plant Hardiness zones represent average lowest temperatures - not the lowest ever or the lowest possible. As USDA Zones are based on average temperatures, it is always possible that your area may experience a rare extreme cold snap, in which plants that have thrived happily in other years could be lost. Past weather records give guidance for plants, but of course, there can be variations in weather.  
• Remember, USDA Zones help guide recommendations for hardiness, but Zones can cross from coast to coast -- they are just one of many factors to use when searching for plants that are best suited for your yard. Elevation, light requirements, soil type, soil moisture, and average rainfall/precipitation are all important factors. 
• When shopping for plants at High Country Gardens, you can use our Shopping Filters for all of these attributes to narrow down your selection. 

For more details, check out this interactive map from NPR with information about changing USDA zone designations.

Frost dates are important for gardeners to know, as they signal the start and end of the gardening season. These charts can help you estimate when to expect the first frost in fall, and the last frost in spring, so that you know when to plant in your garden

See our guide: Frost Date For Garden Planning

Hardiness Zones

• To help you select the right plant for your garden, we list the USDA Plant Hardiness Zones to indicate where a long-lived plant (a perennial or biennial) can survive the minimum winter temperatures. This is where the plant is considered "cold hardy."
• If there are no Hardiness Zones listed, then this plant can successfully survive the winters of the Growing Zones listed.

Growing Zones

• Sometimes a plant will have Growing Zones listed outside of the plant’s Hardiness Zones. 
• If a plant has Growing Zones outside of its Hardiness Zones, it can be grown with a little help from the gardener, treated as an annual, grown as a houseplant, or lifted and stored over the colder months.

For example, let’s look at Hardiness Zones vs Growing Zones for Dahlias:

• Growing Zones = Zones 3-11 
• Hardiness Zones = Zones 8-11 (lift in winter)
• This means that while Dahlias can be grown in Zones 3-11, they will only be winter hardy in Zones 8-11. The tubers can be lifted and stored indoors over winter, or they can be treated as annuals and replanted every year.

For in-depth details, visit the USDA Website. There, you can find a previous version of the map of USDA Zones from 2012-2023.