Friends of the Arboretum Lecture

"The Colorful History of America's Plant Hardiness Zones, Including Our Zone 7(b)"
Thomas Packer, Extension Master Gardener Volunteer of Wake County

  • Thursday, January 13, 2022 – 7:30 pm9:00 pm

How the United States Department of Agriculture Plant Hardiness Zones came to be, what they mean, and why they are still in use almost 100 years after the first plant hardiness maps were developed. The presentation will include a review of early colorful, hand drawn maps from the archives of the Arnold Arboretum at Harvard University as well as the latest computer-generated maps from the USDA.

early hardiness zone map of the United States and Canada (with most of Canada cropped)

Tom Parker

About Tom Packer

Tom Packer is a longtime backyard farmer, citizen scientist, certified Master Gardener volunteer from Wake County, and a winner of the program's Diamond in the Rough award as outstanding member of the program's most recent class. Tom has helped anchor the program's gardening helpline, fielding calls and e-mails from gardeners on a variety of horticultural issues. He also is a moderator of the Facebook group Gardening Carolina for North and South Carolina, a volunteer at the JC Raulston Arboretum, a member of the Gardeners of Wake County club, president-elect of the Rotary Club of Raleigh, and obtained his undergraduate and law degrees from the University of California.

Joining the Online Presentation

​This program is being offered in person as well as online. If you want to join us online, visit the URL below:

In case there are any last-minute changes, please check your e-mail for any updates.

Registration is not needed for the in-person program.

COVID-19 Guidelines

As part of NC State University, the JC Raulston Arboretum follows all of the university's Protect the Pack Community Standards. These can be found online at All visitors to the JC Raulston Arboretum must follow these guidelines. All indoor visitors must wear a face covering at all times while indoors.

Free for members, Department of Horticultural Science staff and faculty, NC State University students, and online participants; otherwise $5.00.
Advance registration is not available for in-person attendees. Check-in available at the door. Registration for online attendees available at
JC Raulston Arboretum, 4415 Beryl Road, Raleigh, NC 27606 and online.
Need directions? Click here.
Free parking is available at the JC Raulston Arboretum and along Beryl Road.
Please write for more information about this lecture.