Your hardiness zone change comes from the USDA releasing a new map in 2023. This map shows warmer winters across most of the country. About half of all US spots shifted into a warmer zone than before so check your area.
When I first checked the new map and saw my zone had bumped up from 6a to 6b, I wondered what it meant for my garden. The good news was that my existing plants were fine. They could already handle colder temps than my new zone required so the change opened up new options for me.
The USDA map update uses climate data from 1991 to 2020 instead of the old range from 1976 to 2005. This shift brought in 15 years of newer weather records that show warmer patterns. The average temp across the country rose about 2.5 degrees Fahrenheit during this period.
Some areas saw much bigger zone shifts than others. Climate Central research found that 95% of locations got warmer since the last map. Reno, Nevada warmed by 9.3 degrees Fahrenheit for one of the biggest jumps. Coastal and northern areas saw the most change.
Your zone shift does not mean you need to rip out your current plants and start fresh with new ones. Plants rated for colder zones will still thrive since they can handle temps below what you now face. A plant hardy to zone 4 will do great in your new zone 6 garden without any changes needed.
The change does expand what you can grow without winter protection in your yard. You might now try plants that were borderline before like certain ornamental grasses or shrubs. Check the zone rating on plants you wanted in the past but skipped because they seemed too risky for your old zone.
Keep in mind that extreme cold snaps can still hit your area even if average temps have risen. The zone rating shows typical low temps over 30 years but polar vortex events can drop below that. I still protect my borderline plants when forecasts show very cold weather coming my way.
You can check your new zone on the USDA website by typing in your ZIP code. Compare it to your old zone and look at what new plants might work in your beds. The warmer rating gives you more choices at the nursery and lets you try options that were too tender before.
Read the full article: Hardiness Zone Map: Find Your Growing Zone
