You may have heard a lot about Hardiness Zones when it comes to plants that will survive in your climate, but Hardiness Zone maps can be a little difficult to read. Here are the Zones of the 20 most populated cities in the United States. (Click on the Hardiness Map to the right to see a larger version and to learn how to use it.)
1. New York City, New York Zone 7b
2. Los Angeles, California Zone 10b
3. Chicago, Illinois Zone 6a
4. Houston, Texas Zone 9a
5. Philadelphia, Pennsylvania Zone 7a
6. Phoenix, Arizona Zone 9b
7. San Antonio, Texas Zone 8b/9a
8. San Diego, California Zone 10b
9. Dallas, Texas Zone 8b
10. San Jose, California Zone 9b
11. Jacksonville, Florida Zone 9a
12. Indianapolis, Indiana Zone 6a
13. Austin, Texas Zone 8b
14. San Francisco, California Zone 10a
15. Columbus, Ohio Zone 6a
16. Fort Worth, Texas Zone 8a
17. Charlotte, North Carolina Zone 7b/8a
18. Detroit, Michigan Zone 6b
19. El Paso, Texas Zone 8a
20. Memphis, Tennessee Zone 7b
I Know My Zone, So Now What?
Now that you know your Hardiness Zone, you can make smart container plant choices. Gardeners who live in Zone 6, for example, can keep plants that are hardy to Zone 6, meaning that plants hardy to Zone 6 will survive the winter in the minimum temperatures of Zone 6, Zone 5, Zone 4 and so on. But container gardeners living in Zone 6 may choose to only grow plants hardy to Zone 5 and not Zone 6. Why? Container plants are less insulated than plants that have their roots in the ground soil, so container plants may freeze quicker and not do as well during the winter. Container gardeners who live in Zone 6 may want to play it safe and only keep container plants outdoors that are hardy to Zone 5, Zone 4, Zone 3 and so on. Any other plants can be overwintered indoors.
Keep in mind that the expected minimum temperature of a certain Zone is not the same every year, so use the Hardiness Zones as guides and don’t take them too seriously. And for other factors, some plants may just not make it through the winter.