USDA Zone 6: Planting & Hardiness Map

What is USDA Zone 6 Planting Zone?

USDA Plant Hardiness Zone 6 is defined as the region where the average annual extreme minimum temperature falls between -10°F to 0°F (-23.3°C to -17.8°C). This definition is based on the average annual extreme minimum temperature over a 30-year period from 1991–2020.

This zone spans landscapes from the Appalachian Mountains to the Great Plains and stretches across 35 U.S. states, including the central United States, with extensions into the Northeast (e.g., Pennsylvania) and parts of the West (e.g., Washington).

Search USDA Zone 6 by ZipCode

USDA Planting Zone 6 Map

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Zone 6 is divided into two subzones: 6a and 6b, each with distinct temperature ranges and growing conditions:

Zone 6a

Zone 6a has an average annual extreme minimum temperature range of -10°F to -5°F (-23.3°C to -20.6°C). This subzone typically experiences:

1. A growing season of approximately 159 days, from the last spring frost on May 4 to the first fall frost on Oct 10
2. Cold winters with consistent snow cover in many areas
3. Warm summers with moderate humidity

Zone 6a covers significant portions of states like Michigan, Ohio, and Pennsylvania, extending into parts of the Northeast and Midwest. In these regions, the climate supports a wide variety of cold-hardy perennials, deciduous trees, and many vegetable crops.

Zone 6b

Zone 6b is slightly milder, with average annual extreme minimum temperatures ranging from –5°F to 0°F (-20.6°C to -17.8°C). Characteristics of this subzone include:

1. 169-day growing season, from the last spring frost on Apr 30 to the first fall frost on Oct 16
2. Moderately cold winters with less consistent snow cover than Zone 6a
3. Warm to hot summers with occasional high humidity levels

Zone 6b is prevalent in states like Missouri, Kansas, and Ohio, and occurs in parts of the Pacific Northwest and Northeast. This subzone provides more planting flexibility, supporting less cold-hardy species.

Microclimates create subtle transitions between subzones, significantly impacting local growing conditions. Determine your exact zone using our interactive color-coded map or zip-based planting zone search tool below.

Zone 6 Frost Dates

In Zone 6, the typical last spring frost comes on May 4 in 6a and April 30 in 6b, and the first fall frost on October 10 in 6a and October 16 in 6b. The table gives the median date for every ZIP code in each subzone and the range that covers 8 of 10 ZIP codes, from NOAA 1991–2020 weather-station records; in 7 of 10 years, the frost comes before the spring date and after the fall date. The growing season is the number of days between the two dates. Frost dates for one garden come from its ZIP code: frost dates by ZIP code.

Subzone	Last spring frost	First fall frost	Growing season
Zone 6a	May 4 (Apr 23–May 19)	Oct 10 (Sep 30–Oct 18)	159 days
Zone 6b	Apr 30 (Apr 17–May 11)	Oct 16 (Oct 4–Oct 24)	169 days

When to Plant in Zone 6?

In Zone 6, plant garlic from October 10 to November 10 and tulip bulbs from October 10 to November 20, the typical windows for Zone 6 ZIP codes. Dates for one ZIP code: When to Plant Garlic and When to Plant Tulip Bulbs.

November is the last month for garlic and spring bulbs in Zone 6: What to Plant in November lists vegetables, flowers, and cover crops by zone. Planting dates for more crops: When to Plant: Planting Dates by ZIP Code.

What are the States of Zone 6 USDA Planting Zone?

1. Arizona

Zone 6 in Arizona occurs in high-elevation areas, primarily within its north-central region. Subzone 6a includes cities like Flagstaff at higher elevations, while 6b extends to areas such as Pinetop-Lakeside. This zone supports drought-tolerant and cold-hardy plants, including yucca species, pinyon pines, and native wildflowers.

2. California

Zone 6 in California is located in high-elevation areas of the Sierra Nevada and other mountain ranges. Subzone 6a includes Mammoth Lakes at the highest elevations, while 6b extends to slightly lower elevations, such as South Lake Tahoe. This zone supports cold-hardy plants, including conifers, alpine wildflowers, and species like penstemon and columbine.

3. Colorado

Zone 6 in Colorado occurs primarily along the Front Range and in the western valleys. Subzone 6a includes Denver, Boulder, and Pueblo, while 6b extends to the lower western valleys, such as Montrose, Delta, and parts of Durango; Grand Junction is zone 7a. This zone supports drought-tolerant plants, including Russian sage, yarrow, and penstemon varieties.

4. Connecticut

Zone 6 occurs in most of Connecticut, with subzone 6a including Torrington in the northwestern hills, and 6b extending to the central and western areas, such as Hartford, Waterbury, and Danbury; New Haven and the coast are zone 7a. This zone supports diverse plants, including rhododendrons, azaleas, and native New England perennials.

5. Idaho

Zone 6 in Idaho occurs primarily in the southern valleys and the northern Panhandle. Subzone 6a includes Hailey in the Wood River Valley and Sandpoint in the north, while 6b extends into lower elevations and sheltered valleys, such as Twin Falls and Coeur d’Alene; Boise is zone 7a. This zone supports drought-tolerant plants, including lavender, sage, conifers, and fruit trees like apples and pears.

6. Illinois

Zone 6 in Illinois occurs in central and southern regions. Subzone 6a includes Springfield in central Illinois, while 6b, a warmer subzone, extends further south and includes Mount Vernon. This zone supports hardy plants, including coneflowers, black-eyed Susans, and hardy hibiscus.

7. Indiana

Zone 6 in Indiana occurs in central and southern regions. Subzone 6a includes parts of Indianapolis in central Indiana, while 6b extends further south and includes Bloomington. This zone supports fruit trees, berry bushes, and hardy plants, including redbud trees, butterfly weed, and hardy geraniums.

8. Iowa

Zone 6 in Iowa occurs in southeastern Iowa. Subzone 6a includes cities like Burlington, Fort Madison, and Keokuk. Average annual minimum winter temperatures range from -10°F to -5°F (-23.3°C to -20.6°C). This subzone supports native, climate-adapted plants, including Black-Eyed Susan, Purple Coneflower, and Butterfly Weed.

9. Kansas

Zone 6 in Kansas occurs in most of the state, with subzone 6a including Manhattan and Atchison in the northeastern region, and 6b extending into eastern and central areas, such as Topeka, Overland Park, and Lawrence; Wichita is zone 7a. This zone supports native grasses and ornamental plants, including little bluestem, coreopsis, and purple coneflower.

10. Kentucky

Zone 6 in Kentucky occurs in the northern part of the state, with only subzone 6b present, covering northern Kentucky and the Bluegrass, such as Covington, Frankfort, and Georgetown; Lexington and Bowling Green are zone 7a. This zone supports diverse plants, including dogwoods, hydrangeas, ferns, and vegetable crops.

11. Maine

Zone 6 in Maine occurs in coastal regions. Subzone 6a covers coastal areas, including cities like Portland, Kennebunkport, and Bar Harbor, while 6b is limited to a few offshore islands and points, such as Vinalhaven and Kittery Point. This zone supports coastal- and cold-tolerant plants, including Highbush Blueberry, Eastern White Pine, and Red Osier Dogwood.

12. Maryland

Zone 6 in Maryland occurs in western Maryland. Subzone 6a includes higher elevations in the Appalachian Mountains, such as Oakland, Frostburg, and Grantsville, while 6b covers lower elevations and valleys. This zone supports mountain-adapted plants, including Redbud, Black Chokeberry, and New England Aster, which thrive in the region’s cool climate and rugged terrain.

13. Massachusetts

Zone 6 in Massachusetts occurs across much of the state. Subzone 6a includes central and western regions with cities like Worcester and Springfield, while 6b extends to coastal and eastern areas, such as Cambridge and parts of Boston. This zone supports diverse plants, including rhododendrons, mountain laurel, maple trees, and native New England species adapted to cool coastal to inland climates.

14. Michigan

Zone 6 in Michigan occurs primarily in southern Michigan. Subzone 6a includes southern interior regions with cities like Grand Rapids and Ann Arbor, while 6b extends along Lake Michigan’s shoreline and into the southeastern corner, such as Detroit. This zone supports hardy plants, including serviceberry, ninebark, clematis varieties, and species that thrive in lake-effect moderated climates.

15. Missouri

Zone 6 in Missouri occurs in northern and central regions. Subzone 6a includes St. Joseph and Hannibal across northern Missouri, while 6b covers central areas and the Missouri River Valley, such as Kansas City and Columbia; St. Louis is zone 7a. This zone supports temperature-resilient plants, including oakleaf hydrangea, purple coneflower, and native prairie grasses that thrive in cold winters and hot summers.

16. Montana

Zone 6 in Montana occurs in valleys and lower elevations of the northwest. Subzone 6a includes Flathead Lake and the Kootenai and Clark Fork valleys, such as Polson and Libby, while 6b is limited to one warm pocket near the Idaho line, at Heron. This zone supports cold-winter and short-season resilient plants, including Rocky Mountain juniper, blue grama grass, and cold-hardy fruit trees like apples and plums.

17. Nebraska

Zone 6 in Nebraska occurs in eastern Nebraska. Subzone 6a includes Lincoln across the eastern third, while 6b is limited to the southeast corner. Omaha straddles the 5b/6a boundary. This zone supports drought-tolerant and temperature-resilient plants, including coreopsis, Russian sage, drought-tolerant perennials, and species adapted to the Great Plains’ cold winters and hot, dry summers.

18. Nevada

Zone 6 in Nevada occurs in higher-elevation areas. Subzone 6a includes the Sierra Nevada, while 6b extends into other mountain ranges. This zone supports native and climate-adapted plants, including sagebrush, rabbitbrush, cold-hardy juniper, and species suited to arid, high-elevation conditions in Nevada’s high desert climate with extreme temperature fluctuations.

19. New Hampshire

Zone 6 in New Hampshire occurs primarily in southern regions. Subzone 6a includes Manchester, Nashua, and Portsmouth across southern New Hampshire, while 6b extends to the southeastern coastal area, such as Seabrook. This zone supports cold-hardy and native plants, including sugar maples, lilacs, ferns, native New England species, and cold-hardy ornamentals that thrive in New Hampshire’s varied topography, from coastal zones to inland hills.

20. New Jersey

Zone 6 in New Jersey occurs in the northwestern highlands. Only subzone 6b is present, covering the hills of Sussex, Warren, and Morris counties, such as Newton, Hackettstown, and Randolph; Newark, Paterson, and Morristown are zone 7. Average annual minimum winter temperatures range from -5°F to 0°F (-20.6°C to -17.8°C). This zone supports cold-hardy plants, including Eastern Redbud, Flowering Dogwood, and American Holly, which thrive in New Jersey’s variable coastal-to-inland climate.

21. New Mexico

Zone 6 in New Mexico occurs in higher-elevation areas. Subzone 6a includes the Sangre de Cristo Mountains, while 6b extends to regions like Santa Fe. This zone supports drought-tolerant and climate-resilient plants, including penstemon, yarrow, conifers, and species adapted to cold winters, arid conditions, and dramatic temperature swings in New Mexico’s high desert climate.

22. New York

Zone 6 in New York occurs in western, central, and eastern regions. Subzone 6a includes Albany and Syracuse in the Hudson Valley and central New York, while 6b extends to western New York and the mid-Hudson Valley, such as Buffalo, Rochester, and Poughkeepsie; New York City and Long Island are zone 7. This zone supports diverse ornamental and edible plants, including butterfly bush, forsythia, hydrangeas, and species adapted to urban, coastal, and inland microclimates.

23. North Carolina

North Carolina zone 6 is located in the western part of the state in the Appalachian Mountains. Subzone 6a includes higher elevations, while 6b covers lower elevations and valleys, with cities like Blowing Rock, Banner Elk, and Newland. Suitable plants for these areas include Fraser Fir, Rhododendron, and Mountain Laurel.

24. Ohio

Ohio’s zone 6 covers a significant area of the state, with subzone 6a having cities like Youngstown (6a) and Mansfield (6a) in parts of the north and west, and 6b extending to central and southern areas and along Lake Erie with cities such as Columbus (6b), Cleveland (6b) and Cincinnati (6b). It is suitable to grow a wide variety of plants here, for example coneflowers, black-eyed Susans, and hardy hibiscus, as well as various perennials, deciduous trees, and some cold-hardy fruit trees.

25. Oklahoma

Zone 6 in Oklahoma is located in the Panhandle. Only subzone 6b is present, covering the western Panhandle, with cities like Guymon and Boise City; Tulsa, Bartlesville, and Tahlequah are zone 7. Suitable plants for these areas include Oklahoma Redbud, Prairie Zinnia, and Indian Blanket, which are adapted to the state’s climate and soil conditions.

26. Oregon

Oregon zone 6 covers the central and eastern parts of the state. Subzone 6a includes higher elevation areas in the Cascade Range and Blue Mountains, with cities like Burns (6a), and 6b covers lower valleys and plateau regions, including cities like Bend (6b). The diverse geography of Oregon and rain shadow effect of the Cascade Range significantly influences the climate in these areas, it is suitable for plants like Ponderosa Pine, Oregon Grape, and Blue Elderberry.

27. Pennsylvania

Pennsylvania’s zone 6 covers its northern, central and western regions, with subzone 6a having cities like Williamsport (6a) and Butler (6a), and 6b covering the larger cities and river valleys such as Pittsburgh (6b), Erie (6b) and Scranton (6b); Allentown is zone 7a. It is suitable to grow plants like Eastern Redbud, Flowering Dogwood, and Black-Eyed Susan.

28. Rhode Island

Zone 6 covers about half of Rhode Island, inland and to the north. Only subzone 6b is present, covering the inland towns, with cities like Woonsocket, Cumberland, and Coventry; Providence, Warwick, and Newport are zone 7a. Suitable plants variety for these areas include Inkberry, Beach Plum, and New England Aster, which can withstand coastal conditions and cold winters.

29. Tennessee

Tennessee zone 6 is limited to the highest ground in the eastern part of the state, in the Appalachian Mountains. Only subzone 6b is present, around Roan Mountain near the North Carolina line. Nearby cities such as Knoxville, Johnson City, and Kingsport are zone 7b. Example of suitable plants for this zone include Tennessee Coneflower, Flame Azalea, and Serviceberry, which are adapted to the region’s topography and climate.

30. Texas

Zone 6 in Texas is limited to small areas in the northern panhandle region, and have cities like Dalhart and surrounding areas; Amarillo itself is zone 7a. Suitable plants for this zone in Texas include Texas Sage, Blackfoot Daisy, and Yucca, which can withstand the region’s cold winters and hot summers.

31. Utah

Utah zone 6 covers much of its northern and central parts, with subzone 6a including cities like Heber City (6a) and Logan (6a) in higher elevations, and 6b covering the lower valleys with cities such as Bountiful (6b) and Springville (6b); Salt Lake City and Provo are mostly zone 7. The presence of the Wasatch Range and Great Salt Lake influences local microclimates here and it is suitable to grow plants like Rocky Mountain Juniper, Utah Serviceberry, and Gambel Oak.

32. Virginia

Virginia’s zone 6 is located in the western and northwestern parts of the state. Subzone 6a includes higher elevation areas in the Appalachian Mountains, with areas like Monterey (6a) in Highland County, and 6b covers some lower valleys and foothills, including towns like Bluefield (6b) and Tazewell (6b); Blacksburg and Roanoke are zone 7. The influence of the Appalachian Mountains create microclimates and suitable plants for these areas include Virginia Pine, Flowering Dogwood, and Redbud.

33. Washington

Hardiness Zone 6 in Washington is located in the eastern part of the state. Subzone 6a includes higher elevation areas in the Cascade Range and northeastern mountains, and 6b covers the Palouse and other lower valleys, with cities like Pullman (6b) and parts of Spokane (6b); Walla Walla is zone 7a. The diverse geography, influenced by the rain shadow effect of the Cascade Range, creates varied growing conditions suitable for plants like Douglas Fir, Vine Maple, and Pacific Dogwood.

34. West Virginia

West Virginia’s zone 6 covers most of the state. Subzone 6a includes higher elevation areas in the Appalachian Mountains, such as Elkins (6a), and 6b covers lower elevations and river valleys, including cities like Parkersburg (6b), Wheeling (6b) and Fairmont (6b); Charleston, Huntington, and Morgantown are zone 7a. The state’s mountainous terrain creates diverse microclimates, the Appalachian Mountains significantly influence the climate, making it suitable for plants like Tulip Poplar, American Beech, and Mountain Laurel.

35. Wisconsin

Zone 6 in Wisconsin is confined to the southeastern part of the state, specifically subzone 6a, which includes parts of the Lake Michigan shoreline and some inland regions, with cities like Milwaukee and Racine. The moderating effect of Lake Michigan creates a warmer microclimate, with average annual minimum winter temperatures ranging from -10°F to -5°F (-23.3°C to -20.6°C). This area is suitable for plants like Sugar Maple, Red Oak, and American Hornbeam, with the lake effect also influencing precipitation patterns.