Zone Map

This map of Minnesota is from the updated 1990 USDA Plant Hardiness Zone Map.The Zone Map provides gardeners with horticultural and meteorological information about the growing conditions of plants. This map shows the two main zones of Minnesota, zones 3 and 4, subdivided with their average minimum temperature.

Zone Map Key Average Annual Minimum Temperature   Selected perennials for Zones 3 and 4

To see a list of selected perennials, point to a zone in the Zone Map Key to the left.

Zone 3 is located in parts of Alaska, lower Canada, and along the upper U.S. border. Though it stays cold for a good part of the year, you can still plant a large variety of plants in mid-April. If you are planting bulbs, do it by early September to be safe from heavy frosts. Take care to protect your plants with tall borders and shady trees as brisk winds tend to dehydrate plants growing in the frozen soil. Water everything in late autumn so plants don't dry out from the wind.

Zone 3 was divided in 1990 into two areas by the National Arboretum to provide gardeners with even more environmental detail: 3a and 3b.
3a - Minimum temperature of -40 to -35 F (-37.3 to -39.9 C) Places like International Falls, Minnesota and St. Michael, Alaska.
3b - Minimum temperature of -35 to -30 F (-34.5 to -37.2 C) Places like Tomahawk, Wisconsin andSt. Cloud, Minnesota.

Zone 4 has blustery winters and warm summers. The area extends across the upper U.S. from Idaho to the Great Lakes. Parts of Connecticut, Delaware, District of Columbia, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, and West Virginia are also included in this zone. Opportunities abound to grow lots of plants, so you can spend the long winters planning for beautiful gardens.

Zone 4 was divided in 1990 into two areas by the National Arboretum to provide gardeners with even more environmental detail: 4a and 4b.
4a - Minimum temperature of -30 to -25 F (-31.7 to -34.4 C) Places like Minneapolis/St.Paul, Minnesota and Lewistown, Montana.
4b - Minimum temperature of -25 to -20 F (-28.9 to -31.6 C) Places like Northwood, Iowa and Nebraska.

Median Frost Dates

When choosing plants, you sometimes need to know the last frost date in spring and the first frost date in fall. Every year this date will be different. This chart was calculated for the years 1948-1992 and shows the medium frost dates (32 F) and other low temperature thresholds for spring and fall.

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