New England Hardiness Zones
More on Hardiness Zones, Zone Map of North America.
National Arbor Day Foundation - 2006 zone update reflects recent warmer temperatures.
Interpreting Your Zone
How to determine if plants will overwinter for you, from Plant Delights Nursery.
Canadian zone map
Heat Zone Map
From the American Horticultural Society
A Gardener's Guide to Zone Maps
- A summary of several commonly used zone maps.
Printer friendly black and white version of New York Hardiness Zone map.
Update 1/26/2012: USDA has issued a revised Hardiness Zone map. See: New hardiness zone map for New York Here's the new map for New York. Visit the new USDA Plant Hardiness Zone Map website for more information.
Click for larger image.
Hardiness Zone information helps you determine which herbaceous perennials and woody trees, shrubs and vines will survive winters where you garden.
Click on the map above and locate your site on the larger map. Use the key on the map to determine your Hardiness Zone. Consult the Hardiness Zone Summary page for more information about your Zone.
Zones are based on the average annual minimum temperatures as determined by the USDA for the years 1974 to 1986. For example, if you garden in Zone 5a, Hardiness Zone Summary suggests you can expect that your low winter temperature may drop as low as -15 F and -20 F. Based on the list of indicator plants on that page, you can expect that flowering dogwood (Cornus florida) will be survive winters where you live, but not in colder Zones.
Look for Hardiness Zone information on plant tags when you purchase perennial plants, or ask the nursery staff if you don't see it listed. This information is standard in plant catalogs and gardening and landscaping publications, though you may see differences of a Zone or so depending on the source.
The maps aren't foolproof, but can provide you with an estimate of your Hardiness Zone. Your site may be a Zone higher or lower due to inaccuracies in the map. Local microclimates or USDA estimates and approximations may explain some of the differences.
For example, if you are near a large body of water, such as one of the Finger Lakes, the water may moderate air temperatures nearby and make your site a Zone warmer. If you are in a valley where cold air settles during clear winter nights when radiational cooling occurs, you may be a Zone colder. Urban areas are often a Zone warmer than surrounding rural areas.
Contact your county's Cornell Cooperative Extension staff for local advice on microclimates.
Even microclimates within your yard may affect whether or not your plants can survive. For example, a protected spot on the south side of your house may actually be a Zone warmer than an exposed spot on the north side.
Do not confuse this map with older Zone maps. (For example, the Arnold Arboretum zone map that still appears in some publications.) The USDA undertook this revision in 1990 because landscape plants that survived well in the decades from 1940 to 1970 were no longer surviving. The USDA found that the ranges of temperature and moisture during the 1970s and 1980s were wider than in previous decades, resulting in some plants no longer being hardy in some Zones.
Here is more information that will help you pinpoint your Hardiness Zones and better determine which plants will survive and thrive where you live:
- The indicator plants for each Zone (see summary) should thrive in that Zone, assuming other plant needs are met. They may survive in a colder Zone, but will probably perform poorly.
- In general, healthy plants that are well-matched to their site (correct sun exposure, healthy soil, good drainage, suitable pH range, etc.) are more likely to overwinter well.
- Plants usually survive well if temperatures cool gradually in fall and early winter, allowing the plant to harden off.
- Do not apply nitrogen fertilizer to plants late in the season as it may cause them to put on a flush of growth that will not harden off properly and stress the plant. If soils and plants are low in potassium, late-season applications may help overwintering.
- Plants in containers or other highly artificial environments are much less likely to overwinter, compared to the same plants properly planted in the ground.
- The moderating effects of snow cover on soil temperature may help some marginal plants overwinter. Protecting plants with a thick layer of mulch may also help.
- Prolonged low temperatures may be more damaging than a single cold night.
- Marginal evergreens can benefit from shade during winter, and may actually survive better on the north side of buildings.
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