Connecticut Plant Hardiness Zones Have Changed

Follow Us For Our Latest Posts, Tips, & Exclusive Facebook Giveaways


Are You Zone Savvy?

If you live in an area of Connecticut that the United States Department of Agriculture (USDA) just bumped into a warmer plant hardiness zone, you may be in for a pleasant surprise. Being in a warmer zone, even if only slightly warmer, opens up new planting possibilities.

The USDA establishes plant hardiness zones based on average temperature minimums over time. The new hardiness zone map reflects weather information collected from 1976 through 2005 which boosted some parts of Connecticut into a slightly warmer zone.

As you can see below, only the northwest corner held onto chilly zone 5b status (average minimum temperatures from -15 to -10 degrees Fahrenheit). Covering most of the state is Zone 6, split into colder 6a and warmer 6b with average temperature minimums from -10 to -5 degrees and -5 to 0 degrees, respectively. Connecticut’s new zone, 7b with temperature minimums between 0 and 5 degrees, runs along the shoreline from New Haven westward to the New York state line.

Credit: USDA Plant Hardiness Zone Map, 2012. Agricultural Research Service, U.S. Department of Agriculture. Accessed from https://planthardiness.ars.usda.gov.

It’s now easier to exactly pinpoint the zone in which your property is located, a feature particularly useful for locations near zone borders. Simply enter your zip code into the interactive version of the map. Portions of Stamford, for example, now fall in zone 7a while others remain zone 6b.

A plant hardy in zones 3 to 7 is well suited for all of Connecticut’s hardiness zones as long as the plant is properly located to meet its light, soil, moisture and wind exposure needs. A plant listed hardy in zone 7 to 9, however, will likely only survive in Connecticut’s chillier zone 6 if given extra winter protection.

Most plant tags list hardiness zone ranges. If this vital information is missing, ask a nursery professional what hardiness zone the plant prefers so you have a clear understanding of what the plant needs before you bring it home to your garden.

Joene Hendry, an Accredited Organic Land Care Professional (AOLCP), designs and maintains gardens in the southeastern Connecticut River valley and blogs about gardening in Connecticut at https://www.joenesgarden.com.

Follow Us For Our Latest Posts, Tips, & Exclusive Facebook Giveaways