Our Guide to the USDA Gardening Zones

Map of USDA gardening zones showing average annual minimum temperatures across the United States labeled with zones — Credit:
Kailey Whitman

Even if you're a gardening novice, you've likely heard the term "gardening zones." This refers to the United States Department of Agriculture's (USDA) Plant Hardiness Zone Map, which breaks the entire country into 10-degree Fahrenheit zones based on the average annual extreme minimum winter temperature in that area.

Knowing your zone gives you a better understanding of which plants will thrive in your region based on the weather patterns. Ahead, gardening experts explain how to identify which zone you live in and provide suggestions for the best plants to grow in your garden depending on your zone.

Jennifer and Adam O'Neal, owners of PepperHarrow Farm and co-authors of Small Farm, Big Dreams: Turning A Flower-Growing Passion into a Successful Floral Business
Teri Speight, master gardener and author of Black Flora: Profiles of Inspiring Black Flower Farmers and Florists
Justin Hancock, a horticulturist at Costa Farms
John Clements, the director of gardens at the San Diego Botanic Gardens

What Are Plant Hardiness Zones?

A hardiness zone is a region defined by its average minimal temperature. These zones help gardeners understand which plants will thrive in their climate, say Jennifer and Adam O'Neal, owners of PepperHarrow Farm. The hardiness zones defined by the USDA range from zone 1 (coldest) to zone 13 (warmest).

Plant Hardiness Subzones

Each hardiness zone is split into two subzones, labeled "a" and "b," which differ by 5 degrees Fahrenheit. For example, zone 7 has a freezing range between 0 and 10 degrees Fahrenheit. In zone 7a, average freezing temperatures range between 0 and 5 degrees Fahrenheit; in zone 7b, average freezing temperatures range between 5 and 10 degrees Fahrenheit.

Understanding your subzone will help you make more precise decisions about your garden. To determine your subzone, first find your overarching zone on the USDA's map—then do a narrow location search with your zip code to find out whether you're "a" or "b."

Why It's Important to Know Your Plant Hardiness Zone

Knowing your hardiness zone will tell you which plants will—and will not—thrive in your garden. For example, if you are in zone 13 and grow a plant that prefers a colder climate, it likely won't be able to withstand the heat and may die. Knowing your zone will also tell you when your first and last frost dates are. "The first and last frost dates are important in deciding when it is safe to plant outdoors, as well as when to take tender plants indoors," says master gardener Teri Speight.

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The Plant Hardiness Zones by Region

The USDA also breaks down gardening zones by region across the U.S. These regions include North Central, Northeast, Northwest, South Central, Southeast, and Southwest. To better understand every region, look to these descriptions, which include the states in each region, the zones that run through them, and their typical climate conditions.

North Central

A map showing planting hardiness zones for a central region of the United States using color codes and temperature ranges — Credit:
Kailey Whitman

The climate is generally cooler across this region of the U.S.

Zones: 2 through 5
States: North Dakota, South Dakota, Minnesota, Wisconsin, Nebraska, Iowa, Illinois, Kansas, and Missouri

Northeast

Temperatures vary greatly across the Northeast and encompass a wide range of zones.

Zones: 1 through 7
States: Michigan, Indiana, Ohio, Kentucky, Virginia, West Virginia, Pennsylvania, New York, New Jersey, Maryland, Delaware, Connecticut, Massachusetts, New Hampshire, Maine, Vermont, and Rhode Island

Northwest

Conditions in the Northwest are typically wet in the winter and dry in the summer.

Zones: 3 to 9
States: Washington, Oregon, Montana, Idaho, Wyoming, and Northern California

South Central

This region is generally defined as the area from the southern Great Plains to the Gulf of Mexico, say the O'Neals.

Zones: 6 through 9
States: Parts of Texas, Oklahoma, Arkansas, Louisiana, Mississippi, and Alabama

Southeast

The last frost date in this region typically occurs in April, but note that South Florida does not experience a frost at all, says Justin Hancock, a horticulturist at Costa Farms.

Zones: 7 to 10
States: Tennessee, North Carolina, South Carolina, Mississippi, Alabama, Georgia, and Florida

Southwest

With the extreme heat in this region, it's helpful to understand the high temperatures that peak during summer and the extreme lows in winter. "The Sunset zone maps are more precise than the USDA's since they factor in not only winter minimum temperatures, but also summer highs," says John Clements, the director of gardens at the San Diego Botanic Gardens.

Zones: 3 to 10
States: California, Nevada, Utah, Colorado, Arizona, and New Mexico

Mixed border in an English cottage garden. — Credit:
R A Kearton / Getty Images

Popular Plants to Grow in Your Region

There are many plants that thrive in each zone. Consider these expert recommendations when choosing varieties for your garden.

North Central (Zones 2 through 5)

Consider these favorites from the O'Neals when planting in the North Central region of the U.S.

Groundcover	Creeping thyme (Thymus serpyllum) is a low-maintenance ground cover that can grow in zones 2 through 9. "It produces masses of small, fragrant flowers in spring," the O'Neals say. "Creeping thyme prefers well-draining soil and full sun."
Vine	Clematis is a vining plant that thrives in various growing conditions. "Not only does it make a beautiful flower, its foliage is dainty and beautiful, as well," they say.
Perennial	Coneflowers (Echinacea) are native perennials that are adapted to this region. "They produce large flowers in a variety of colors that attract pollinators," they say. "They prefer well-draining soil and full sun." These thrive best in zones 3 through 9 when they are planted in spring or fall.
Shrub	Lilac (Syringa) is an heirloom shrub that grows best in zones 2 through 8. It produces fragrant flowers in spring and prefers full sun and well-draining soil. It can be planted in spring or fall.
Tree	Red maple (Acer rubrum) is a fast-growing tree that grows well in a variety of soil types and light conditions. It can be planted in zones 3 through 9. It's best planted in the spring or fall.

Northeast (Zones 1 through 7)

Speight recommends growing these plants in the Northeast.

Groundcover	Sweet woodruff (Gallium odoratum) grows best in part shade. "It usually grows 10 to 12 inches high with a spread of 18 to 20 inches," Speight says. This plant loves damp borders and grows tiny white flowers and green foliage. It grows best in zones 3b through 7.
Vine	Clematis can also be grown in the Northeast. "Great for zones 4 through 8, this vine loves a full to part sun environment," says Speight. "A little compost or aged manure in the spring will keep this plant well fed." Use mulch to keep the roots cool.
Perennial	Hellebore (Helleborus) is a dependable perennial best grown in zones 3 through 8. "One major reason I love this plant is the upkeep is minimal," she says. "When the previous season's foliage begins to look tattered, cut them back at the base. This allows the blooms to stand tall and the new leaves to emerge." This flower begins blooming in late January and continues through May.
Shrub	Great for zones 3 through 8, the osier dogwood (Corns servicea) can grow throughout all seasons in full sun to part shade. "The beauty of this shrub is revealed when pruning out the old growth," says Speight. "After a spring pruning, the new growth emerges in shades of red or coral. This color shows off in the winter garden, especially when there is snow or against an evergreen backdrop."
Tree	Redbud (cercus canadensis) is a low-maintenance native tree that grows in zones 4 to 9. "From the prolific pink blooms along the branches in the spring, to the heart-shaped leaves, what is not to love?" says Speight. "It can grow in full sun or partly shaded environments. Redbuds can grow in less than perfect soils such as clay to loamy, well-draining soils."

Northwest (Zones 3 through 9)

Try growing these expert-approved suggestions (including a few favorites from Martha) if you live in the Northwest.

Groundcover	'Black Scallop' bugleweed (Ajuga reptans 'Binblasca' Black Scallop) grows best in zones 3 through 9. Martha has even grown this in her garden and loves its glossy foliage and bright blue flowers.
Vine	Best grown in zones 4 through 8, climbing hydrangeas thrive in the Northwest. These plants need rich soil and can live in full sun, partial shade, and deep shade.
Perennial	Coneflowers (Echinacea) provide intrigue well into autumn. "Thriving in zones 3 through 9, these perennials add beauty to the garden when in bloom over the summer months," says Speight.
Shrub	Boxwood (Buxus), one of Martha's favorite shrubs, grows in zones 5 through 9. Boxwoods are both fragrant and deer-resistant.
Tree	Evergreen trees enjoy the cool, moist conditions of the Northwest. Martha says these trees maintain their green foliage throughout the entire cold-weather season.

South Central (Zones 6 through 10)

The O'Neals share their recommendations for plants to grow in this region.

Groundcover	Creeping phlox (Phlox subulata) is a low-maintenance groundcover that is well-suited to the South Central region. It prefers well-draining soil and full sun, and can be planted in zones 7 through 10. Plant in spring or fall.
Vine	Carolina jessamine (Gelsemium sempervirens) is a fast-growing vine that produces fragrant yellow flowers in spring. It prefers well-draining soil and full sun and can be planted in zones 7 through 9. It is best planted in spring or fall.
Perennial	Black-eyed Susan (Rudbeckia hirta) is a tough native perennial that produces masses of yellow flowers throughout summer. It prefers well-draining soil and full sun and can be planted in zones 3 through 9. It is best planted in spring or fall.
Shrub	Crepe myrtle (Lagerstroemia indica) is a popular shrub or small tree that produces showy flowers in various colors throughout summer. It prefers well-draining soil and full sun and can be planted in zones 7 through 10. It is best planted in spring.
Tree	Southern magnolia (Magnolia grandiflora) is a native broadleaf evergreen tree beloved for its attractive dark green leaves and large, fragrant flowers. It prefers well-draining soil and full sun and can be planted in zones 7 through 10. It is best planted in spring or fall.

Southeast (Zones 5 through 10)

If you want to grow plants in the Southeast, consider these ideas from Hancock.

Groundcover	Lilyturf (Liriope muscari) is a great groundcover. "This drought-tolerant evergreen grows in sun or shade, and its variegated leaf selections add a lovely note to the landscape," Hancock says.
Vine	Jasmine (Jasminum), a powerfully fragrant vine with star-shaped flowers, thrives in this region.
Perennial	Sage (salvia) is a great perennial for this region. Salvia 'Black and Blue' is one of Hancock's favorites, as it blooms year-round in the Southeast.
Shrub	Rosemary (Rosmarinus officinalis) is a landscape plant that grows throughout the Southeast. It is deer- and rabbit-resistant, drought tolerant, and fragrant.
Tree	One of Hancock's favorite trees for this region is red maple (Acer rubrum). "It's native to the region and is a reliable source of bold autumn color," he says.

Southwest (Zones 3 through 10)

Consider these expert-approved plants that thrive in the warm, dry conditions of the Southwest.

Groundcover	White clover (Trifolium repens) is a ground cover that can grow in this region, as it thrives in temperatures ranging from 50 to 85 degrees Fahrenheit in the spring.
Vine	Crossvine (Bignonia capreolata L.) thrives when planted in full sun and well-draining soil. Once it is watered deeply during the first growing season, the plant will develop a sustainable root system.
Perennial	Poppies (Papaver) grow best in zone 7 in areas with low moisture and full sun. They need frequent watering during the germination period, but are drought-tolerant once established.
Shrub	Leadworts (Plumbago) like full sun and light, well-draining soil. The evergreen grows in zones 9 through 11 and needs deep watering in the first growing season.
Tree	Avocado trees (Persea americana) grow in hot, tropical conditions in zones 9 through 11. This tree needs four to six hours of sunlight, well-draining soil, and deep watering. It is drought-tolerant once established.