Kentucky Hardiness Zones

The Parklands of Floyds Fork, Louisville, Kentucky


Danita Delimont / Getty Images 

It's relatively easy to have a thriving garden in the state of Kentucky, as long as you select the best plants for the state's USDA growing zones. Kentucky experiences regular rainfall, a long growing season, and mild winters—an ideal combination for cultivation. Since the conditions are so favorable, Kentucky residents have a wide variety of trees, shrubs, flowers, and vegetables to choose from when planting their landscaping and gardens.

Understanding USDA Zones

Developed by the United States Department of Agriculture (USDA), the USDA zone system delineates geographically defined areas marked by the minimum temperatures of that zone. The goal is to distinguish which areas certain plants can thrive in based on the vegetation's hardiness. The zones—often found on plant or seed labels—give landscapers and gardeners a guide to follow when growing trees, flowers, fruits, and vegetables.

For example, if a plant is described as "hardy to zone 10," it's assumed the plant can thrive as long as the temperature does not fall below 30 degrees Fahrenheit/-1 degree Celsius. A plant that is "hardy to zone 7" could succeed in an area with an annual low temperature of around negative 10 degrees Fahrenheit/17 degrees Celsius.

Kentucky USDA Zones

Three USDA zones are found in the state of Kentucky: 6a, 6b, and 7a. The majority of the state is designated zone 6b, where temperatures can drop as low as -5 degrees Fahrenheit/-20.6 degrees Celsius in the winter. There are several small areas of higher elevation that are considered zone 6a, where temperatures can dip to negative 10 degrees Fahrenheit/-23.3 degrees Celsius on the coldest days of the year. The southwestern corner of Kentucky falls under zone 7a and experiences the highest temperatures of the state, with lows bottoming at 0 degrees Fahrenheit/-17.8 degrees Celsius.

To survive in Kentucky, plants need to be able to tolerate high temperatures and humidity, as the state experiences both in the warmer months. Because of these hot summers, some Kentucky gardeners have luck with plants typically grown in higher zones. For example, fig-trees have been known to thrive when planted in direct sunlight in Kentucky's zone 7 areas, while they're normally a tree grown in zones 8-10.

Native Kentucky Plants

Plants that are native to Kentucky are the most likely to thrive in the state's hardiness zones. There are many benefits to choosing native plants for your garden and yard—they require less care, watering, and are more resistant to disease. Native plants are also non-invasive and they won't cause harm to their surroundings.

Some popular Kentucky native plants and trees include:

For a more extensive list, visit the Kentucky Native Plant Society to learn more about the benefits of native plants and what grows well in the state. If you'd like to purchase native plants for your landscaping, you can find the nearest retailer by referencing the society's directory of Kentucky native plant nurseries.