New Hardiness Zone Map Meets the Digital World

USDA's new plant hardiness zone mapThe new digital USDA hardiness map acknowledges that microclimates exist within small areas. Image: USDA

The USDA has released its new and improved digital Plant Hardiness Zone Map. It’s about time.

Welcome to the 21st century, USDA Plant Hardiness Zone Map!

The new, digital map, the first update since 1990, lets you pinpoint the climate zone you live in and, consequently, select plants for your landscaping most likely to survive the lowest temperature in your yard.

“The old map was not web-friendly, because there was no web when it was created,” says Kim Kaplan of the Agricultural Research Service for USDA, which spent about five years creating the interactive map.

Unlike the previous maps, where wide color bands signified broad temperature patterns across the country, the new map acknowledges that microclimates exist within small areas. Your town can exist in zone 6b, while a town 1 mile away exists in 7a.

Just type in your Zip code, and the map reveals your:

  • Plant hardiness zone
  • Average low temperature
  • Low temperature range
  • Latitude
  • Longitude

“Instead of these big swaths of colors that go across the country, you have a lace doily where zones wrap around each other,” Kaplan says. “There are no straight lines. Where in the past you have had two hunks of zones in Nebraska, you might find six different zones.”

If you’re a new gardener, this finely tuned information will help you match your hardiness zone to plants most likely to survive in your garden. If you’re an experienced gardener, the info will help you decide if it’s wise to “push” your zone and try plants that thrive in neighboring zones.

Of course, no map can indicate “nanoclimates” that exist within your yard. A shaded patch, for instant, can fall into a different zone than a sun-drenched patch.

“All maps are only a guide,” Kaplan says. “Nothing is going to be more accurate than the knowledge a gardener has learned about his own garden.”

Do you pay attention to hardiness zones when you choose plants? Is your zone different than you thought it was?