Understanding Gardening Zones: What Plant Hardiness Zone Am I In?

Having a successful garden is not just about soil quality or how often you water it. A lot depends on the type of plants you choose and whether or not they are suited to the climate in which you live—and which outdoor plants you cannot kill too easily.

Learning the basics of gardening zones, aka plant hardiness zones, is crucial for picking perennial flowers, trees, shrubs, and herbs that will thrive in your garden. Whether you live in Alaska or Arkansas, here is what you need to know.

What Are Gardening Zones?

Hardiness or gardening zones refer to the United States Department of Agriculture’s Plant Hardiness Zone Map (pictured above), which tells growers which plants are most likely to thrive in their location based on how cold it gets in the winter.

This is helpful information for beginner gardeners looking for the basics and experienced green thumbs alike. If you’re still unsure about how to plan your garden, call a gardener near you for help.

How Are the Hardiness Zones Determined? 

There are 13 zones numbered from 1 through 13, which are in 10-degree Fahrenheit increments. There are also half zones, which are in five-degree Fahrenheit increments. For example, there are two half zones for zone 1: 1a and 1b. The coldest zone is 1a, with temperatures between -60 and -55 degrees Fahrenheit. On the opposite end of the spectrum is the warmest zone, 13b, which is 65 to 70 degrees Fahrenheit.

Researchers calculated the average coldest temperatures of each area between 1991 and 2020 based on data from over 13,400 weather stations. From there, scientists assigned a zone for each area of the United States. The map was a joint effort between USDA Research Services and Oregon State University’s PRISM Climate Group.

The 13 Plant Hardiness Zones

The U.S. contains 13 full hardiness zones based on the average annual minimum winter temperature. Each main zone covers a 10-degree-Fahrenheit temperature range.

The 13 zones are further divided into A and B half zones that cover a five-degree-Fahrenheit temperature range. The half zones can further help growers narrow down which plants will thrive in their areas. 

Zone 1: -60˚ to -50°F 

• 1a: -60˚F to -55°F (-51˚C to -48°C) 

• 1b: -55˚F to -50°F (-48˚C to -46°C) 

• Zone 1 region: parts of Alaska

Plants that do well in Zone 1 include lily of the valley, goldenrod, dwarf birch, tomatoes, and beans.  

Zone 2: -50˚F to -40°F

• 2a: -50˚F to -45 °F (-46˚C to -43°C)

• 2b: -45˚F to -40 °F  (-43˚C to -40°C)

• Zone 2 region: parts of Alaska

Plants that do well in Zone 2 include Iceland poppies, American cranberry bushes, carrots, onions, and Swiss chard. 

Zone 3: -40˚F to -30°F 

• 3a: -40˚F to -35°F (-40˚C to -37°C)

• 3b: -35˚F to -30°F (-37˚C to -34°C)

• Zone 3 region: Northwest, Upper Midwest, Northeast, and parts of Colorado

Plants that do well in Zone 3 include hostas, Cupid cherries, asters, asparagus, garlic, and cucumbers. 

Zone 4: -30˚F to -20°F 

• 4a: -30˚F to -25°F (-34˚C to -32°C) 

• 4b: -25˚F to -20°F (-32˚C to -29°C)

• Zone 4 region: Northwest, Upper Midwest, and parts of Arizona and New Mexico

Plants that do well in Zone 4 include bee balm, phlox, coneflowers, eggplant, thyme, and pumpkins. 

Zone 5: -20˚F to -10°F 

• 5a: -20˚F to -15°F (-29˚C to -26˚C)

• 5b: -15˚F to -10°F (-26˚C to -23°C)

• Zone 5 region: Midwest, Northeast, Southeast, and California

Plants that do well in Zone 5 include black-eyed Susans, lavender, spinach, and Honeycrisp and Pink Lady apples. 

Zone 6: -10˚F to 0°F 

• 6a: -10˚F to -5 °F (-23˚C to -21°C)

• 6b: -5˚F to 0°F (-21˚C to -18°C)

• Zone 6 region: Midwest, South, Southeast, parts of Montana, parts of Maine, and parts of Texas

Plants that do well in Zone 6 include Floribunda rose, oregano, coriander, peaches, and bush beans. 

Zone 7: 0˚F to 10°F 

• 7a: 0˚F to 5 °F (-18˚C to -15°C)

• 7b: 5˚F to 10°F (-15˚C to -12°C)

• Zone 7 region: Many states across the country partly fall in Zone 7

Plants that do well in Zone 7 include butterfly weed, clematis, peonies, arugula, Bing cherries, and Fuji and Granny Smith apples. 

Zone 8: 10˚F to 20°F 

• 8a: 10˚F to 15°F (-12˚C to -9°C)

• 8b: 15˚F to 20°F (-9˚C to -7°C)

• Zone 8 region: South, Washington, D.C., Maryland, Virginia, and parts of Alaska

Plants that do well in Zone 8 include Asiatic lilies, hardy geranium, watermelons, hot peppers, okra, Meyer lemons, rosemary, and sage. 

Zone 9: 20˚F to 30°F 

• 9a: 20˚F to 25°F (-7˚C to -4°C)

• 9b: 25˚F to 30°F (-4˚C to -1°C)

• Zone 9 region: South, Southeast, Southwest, and parts of Washington, Oregon, and Hawaii 

Plants that do well in Zone 9 include wisteria, dahlias, rhododendrons, basil, avocado, olives, and mandarin oranges. 

Zone 10: 30˚F to 40°F 

• 10a: 30˚F to 35°F (-1˚C to 2°C)

• 10b: 35˚F to 40°F (2˚C to 4°C)

• Zone 10 region: Southwest, South, and parts of California

Plants that do well in Zone 10 include agave, African lilies, aloe, geraniums, ginger, peanuts, bananas, and jicamas. 

Zone 11: 40˚F to 50°F 

• 11a: 40˚F to 45°F (4˚C to 7°C)

• 11b: 45˚F to 50°F (7˚C to 10°C)

• Zone 11 region: Southern California, Florida, and parts of Hawaii and Puerto Rico

Plants that do well in Zone 11 include bougainvillea, ponytail palms, lemongrass, mangos, macadamias, and sweet peas. 

Zone 12: 50˚F to 60°F 

• 12a: 50˚F to 55°F (10˚C to 13°C)

• 12b: 55˚F to 60°F (13˚C to 16°C)

• Zone 12 region: parts of Hawaii and Puerto Rico

Plants that do well in Zone 12 include Musaceae, heliconia, Marantaceae, African breadfruit, cilantro, black pepper, and tropical almond. 

Zone 13: 60˚F to 70°F 

• 13a: 60˚F to 65°F (16˚C to 18°C)

• 13b: 65˚F to 70°F (18˚C to 21°C)

• Zone 13 region: parts of Hawaii and Puerto Rico

Plants that do well in Zone 13 include tropical flowers and those that do well in Zone 12.

How to Use Hardiness Zones to Garden

1. Find your state’s hardiness zone below. Click on the link in the header to see a detailed hardiness zone map of your state.

2. Shop for perennial plants using these zones as a guide. Plants often thrive in multiple zones and even across large temperature ranges. Blueberries, for instance, work for Zones 3, 4, 5, 6, 7, 8, and 9. Certain varieties, however, are better suited for warmer climates, so it is important to see exactly what varietal you are buying.

3. Shop for annual plants using these zones. While the USDA’s zones are primarily to help growers determine which perennials to buy, some annuals include zone information, too. This can help you determine when to plant your annuals. For instance, gardeners who live in Zone 8 can still plant spinach—a plant that thrives in the cold—as long as they plant it in the winter. Others might be better off waiting to garden in the early spring.

4. When in doubt, choose native plants. Plants that are native to your area have not only been proven to thrive where you live but also attract local pollinators.

If these steps are overwhelming for you, hire a landscaper near you to help. They can recommend the right plants and flowers for your yard, and can even help you plant them.

Hardiness Zones by State

The table below serves as a jumping-off point to help you figure out which hardiness zone you live in. Since there are multiple zones in each state, you should take the time to check out the USDA Plant Hardiness Zone Map website and download your state or territory’s map.

When Was the Last Time the Hardiness Zone Map Was Updated? 

The last update to the Hardiness Zone Map was published in November 2023. Prior to that, the map had not been updated since 2012. The newer map incorporates data from as recent as 2020, while the 2012 map used data through 2005. Researchers also utilized data from 5,429 more weather stations for the newest map, compared to the 2012 one.

Notably, half of the country shifted to a half-zone warmer than before. The USDA noted that this increase in zones is not necessarily indicative of global climate change.