By Amy-Lynn Albertson
N.C. Cooperative Extension

The big news in the gardening world in the last couple of weeks is the Plant Hardiness zone maps have shifted. Where we are in Rowan County has moved from zone 7a-7b to zone 8. What does that mean you ask? Well, it means it is getting warmer. The USDA hardiness zone maps are maps of the average minimum temperature over 30 years. Plant hardiness zone designations represent what’s known as the “average annual extreme minimum temperature” at a given location during a particular period (30 years, in this instance). These designations do not reflect the coldest it has ever been or will be at a specific location but simply the average lowest winter temperature for the area over a specified time.

Low temperature during the winter is a crucial factor in the survival of plants at specific locations. Compared to the 2012 map, the 2023 version reveals that about half of the country shifted to the next warmer half zone, and the other half remained in the same half zone. That shift to the next warmer half zone means those areas warmed somewhere in the 0-5 degrees range; however, some locations experienced warming in the 0-5 degrees range without moving to another half zone.

These national differences in zonal boundaries are primarily a result of incorporating temperature data from a more recent period. The 2023 map includes data measured at weather stations from 1991 to 2020.

If you started your garden before 2012, subtle climate changes could explain why harvest times and dates of first and last blooms have shifted. And if you’ve been paying close attention to the more sensitive plants in your garden in the heat of summer or the hardier plants during the winter chill, things may have changed since then as well. Over the last 10 years, plants that I used to say might be risky to grow here because of the cold, I now say go for it. As the climate changes, we will see more and more plants that grew at the beach be common here in the Piedmont. In 2024 the Rowan County Master Gardeners volunteers will take part in a national research project taking data on oak tree species looking at how southern species of oak can survive in more northern climates due to climate change.

The Extension Master Gardener program is a statewide network of volunteers and Extension educators working in N.C. Cooperative Extension county centers and on N.C. State campus. Through education and outreach, we connect people with the benefits of gardening and empower North Carolinians to cultivate healthy plants, landscapes, ecosystems and communities. N.C. Cooperative Extension Rowan County Center will be offering the N.C. State Extension Master Gardener training in 2024.  The course is a horticulture 101 for the home gardener that prepares you to become N.C. State Extension Master Gardener volunteer. In Rowan County, our Master Gardener volunteers are great ambassadors for Cooperative Extension and the gardening community.

To become a Master Gardener volunteer, you must complete the course, which includes over 50 hours of instruction and hands-on demonstrations. Following the course completion, students must complete 40 hours of volunteer service to complete their certification. Taking data for research projects is just one of the ways volunteers can get volunteer hours. There are many opportunities with community gardens, at the farmers market, 4-H, school programs, garden demonstration events and so much more. There will be an information meeting about the Master Gardener Program on Dec. 6 at the Rowan County Extension Center from 2-3 p.m. If you are curious about the Master Gardener Program, this is your opportunity to learn more. There is no registration necessary; just come to the meeting. If you can’t make the meeting or have questions, call me, Amy-Lynn Albertson, at 704-216-8970 or email alalbert@ncsu.edu.

Amy-Lynn Albertson is director of the Rowan County Extension.