At the end of November 2023, the U.S. Department of Agriculture (USDA) released a new version of its Plant Hardiness Zone Map. This is the first update since 2012. The zones described on the map are based on the average minimum temperature each winter across the U.S. Gardeners and landscapers use the zones as guides to determine which perennial plants are hardy in a given area.
In the 2012 map, Texas fell in Zones 6a through 10a. The zones have shifted slightly in the new map, putting Texas in the 6b to 10b range. This means that growing recommendations in your area might have changed based on the new USDA data.
What Zone Are We In?
Richardson, TX was in Zone 8a (average minimum 10-15 °F) in 2012 and is now in Zone 8b (average minimum 15-20 °F). The USDA adjusted the zone because the average coldest temperature in the area went up by 4 °F.
Most of the Dallas-Fort Worth area is now in Zone 8b, though some counties northeast of the metroplex are in Zone 8a. Click here to open the official USDA hardiness zone map and look up your zone by zip code.
Does the Zone Change Matter?
A change of 4 °F might not seem like much, but it can make a difference. For example, some varieties of flowering maple, or Indian mallow, (Abutilon species) are hardy to Zone 8b, but not necessarily in Zone 8a. If you were in Zone 8a before and are now in Zone 8b, you might be able to grow some sub-tropical plants that wouldn’t have survived a few years ago.
The warmer temperatures can mean a change for plants that love cool weather as well. You might find that you can plant cabbage, broccoli, leafy greens, violas, and other plants that do well in the cold weather earlier in the year than you used to or that some might survive all winter.
The same temperature changes that led to the updated USDA hardiness zone map might also have affected your location’s first and last frost date. Frost dates are based on U.S. Climate Normals data from 1991-2020 collected by the National Oceanic and Atmospheric Administration (NOAA). For 2024, the last spring frost in Richardson, TX, was predicted on March 14.
What Hasn’t Changed?
Overall, the zone change shouldn’t have much of an effect on your existing landscape. The same plants that were doing well in your yard all along will keep growing just fine. It might affect how early you plant your garden and when cool-weather plants start to die off in the summer, but not by much.
Also, the way that you garden and landscape isn’t changing. You might be able to plant some more sub-tropical species in the garden, but you’ll use the same tools for gardening that you always have. Of course, if you’re ready to replace some old gardening tools or add to your collection, this spring is a great time to do that. Stop by and see us at Richardson Saw & Lawnmower to find top-quality lawn, landscaping, and gardening tools.
