What Gardening Zone Is Alabama

How to Use Hardiness Zone Information to Figure Out What You Can Grow

Some plants are hardier than others, meaning they can survive colder winter temperatures. The USDA Hardiness Zone Map can help you zero in on the perennials, trees, and shrubs that can tolerate your region's climate.

Let's say you've just heard about a gorgeous perennial or maybe a spectacular shrub that you want to add to your garden. But will it survive in your region? This dilemma is why the USDA Plant Hardiness Zone Map was created. A glance at it, and you can figure out what your hardiness zone is. Terrific, now what? Most hardy plants have a zone rating to indicate where they will survive the winters from year to year. Maybe the plant you have your eye on is hardy in Zones 5-9, and you live in Zone 4. That could be iffy, but you could try it if you don't mind a little risk for the thrill of growing something that normally wouldn't survive in your region. Or, you could play it safe and find another plant that can withstand your area's coldest temperatures. Either way, here's how you can use USDA Plant Hardiness Zones to guide your decision.

2012 hardiness zone map

The most current version of the USDA Plant Hardiness Zone Map was published in 2012.

| Credit: Courtesy of USDA

What Is the USDA Plant Hardiness Zone Map?

You've probably run across the USDA Plant Hardiness Zone Map or references to it in garden magazines and books, as well as on seed packets or in plant catalogs. This map divides the United States into 11 separate zones (each of which are then divided into a and b). Each zone is 10°F warmer (or colder) in an average winter than the adjacent zone. The lower the zone number, the colder the region.

Although factors other than temperature affect a plant's ability to survive in a particular climate, the USDA map is a good starting point when you're trying to decide what to grow, especially if you live in the eastern half of the country. That's because this area is comparatively flat, so mapping is mostly a matter of drawing lines approximately parallel to the Gulf Coast every 120 miles or so as you move north. The lines tilt northeast as they approach the Eastern Seaboard. They also demarcate the special climates formed by the Great Lakes and by the Appalachian mountain ranges. But in other areas of the country, elevation and precipitation can have more of an effect on plant survival than just temperature.

gloved hands planting cranesbill with surrounding mulch

Even if a plant is rated for your hardiness zone, taking proper care of it will improve its chances of surviving in your climate.

| Credit: Marty Baldwin

What You Can Grow in Your Hardiness Zone

For annual flowers such as petunias and vegetables such as zucchini, you don't need to pay attention to hardiness zones because these plants usually complete their life cycle (seed sprouting to seed producing) in a single year. You might see these plants given a zone rating of 0 to indicate they aren't hardy anywhere. But when you're dealing with perennials, vines, shrubs, and trees that typically live for many years, you'll want to find out the coldest temperatures a species is expected to survive and compare that to the zone you're in.

When considering the hardiness zones a particular plant is rated for, think of that information as a guideline, not a guarantee that it will survive in your climate. The list below provides examples of plants that can take the cold in each USDA Hardiness Zone. Only the coldest zone for each listed plant is considered; some of the plants won't thrive in substantially warmer areas. Always check with the source of your plants for information on whether they are well-suited to your area.

Zone 1: Below -50°F

Most gardeners aren't dealing with freezing Zone 1 temperatures; only a few parts of Alaska, including cities such as Fairbanks, fall into this zone. Still, Zone 1 plants can withstand some of the most frigid conditions, because winter temperatures in this Zone can fall below -50°F.

When to Plant: Mid-June

Common Plants:

Netleaf willow (Salix reticulata)
Dwarf birch (Betula glandulosa)
Crowberry (Empetrum nigrum)
Quaking aspen (Populus fremuloides)
Pennsylvania cinquefoil (Potentilla pensylvanica)
Lapland rhododendron (Rhododendron lapponicum)

Zone 2: -50 to -40°F

Again, Zone 2 mostly refers to areas in Alaska, including cities such as Prudhoe Bay and Unalakleet. However, the northernmost tip of Minnesota also falls in Zone 2b, so if you live in or near Pinecreek, you'll want to look for plants that are hardy in Zone 2. Temperatures in Zone 2 can average -40 to -50°F in the winter.

When to Plant: Mid-June

Common Plants:

Paper birch (Betula papyrifera)
Bunchberry dogwood (Cornus canadensis)
Silverberry (Elaeagnus commutata)
Eastern larch (Larix laricina)
Bush cinquefoil (Potentilla fruticosa)
American cranberry bush (Viburnum trilobum)

Zone 4: -30 to -20°F

Zone 4 plants can withstand minimum chilled temps from -30 to -20°F. You can find this zone in Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, and Eastern states such as Northern New York, New Hampshire, and Maine.

When to Plant: Mid-May

Common Plants:

Sugar maple(Acer saccharum)
Panicle hydrangea(Hydrangea paniculata)
Chinese juniper(Juniperus chinensis)
Vanhouffe spirea(Spiraea x vanhouttei)
Crabapple tree (Malus selections)

Zone 5: -20 to -10°F

This zone is another common one for the Midwest and Northeastern states, where humidity stays high during the summers, and winters can reach as low as -20 to -10°F. You can find Zone 5 in states such as Colorado, Nebraska, Iowa, Wisconsin, Illinois, Indiana, Michigan, and New York.

When to Plant: Mid-April

Common Plants:

Flowering dogwood (Cornus florida)
Delphinium (Delphinium selections)
Slender deutzia(Deutzia gracilis)
Boston ivy (Parthenocissus tricuspidata)
Sycamore tree (Platanus occidentalis)
Japanese yew (Taxus cuspidata)

Zone 6: -10 to 0°F

It's the middle of the road for Zone 6. You can find this zone from Pacific Northwest states, such as Washington and Oregon, and stretching over the middle of the U.S. in states such as Kansas, Missouri, Illinois, and all the way through Ohio. Plants in this zone can withstand temperatures of -10 to 0°F.

When to Plant: Mid-April

Common Plants:

Japanese maple (Acer palmatum)
Common boxwood(Buxus sempervirens)
Coralbells (Heuchera)
American holly (Ilex opaca)
Weeping willow (Salix babylonica)

Zone 7: 0 to 10°F

Winters only occasionally hit the negatives in this zone.Plants in Zone 7 can handle temperatures of 0 to 10°F. You can find this zone in upper parts of the West (Washington, Oregon) and down through upper Texas, Oklahoma, and all the way through Virginia and North Carolina.

When to Plant: Mid-April

Common Plants:

Bigleaf maple (Acer macrophyllum)
Atlas cedar (Cedrus atlantica)
Bleeding heart (Dicentra)
English holly(Ilex aquifolium)
Magnolia tree (Magnoliaselections)
Texas rock rose (Pavonia lasiopetala)
Kurume azalea(Rhododendron Kurume hybrids)
English yew (Taxus baccata)

Zone 8: 10 to 20°F

Things are starting to heat up in Zone 8. In this zone, native plants are loving the warmth. Not only that, but plants will start to have a longer growing season in Zone 8. You can find this zone covering the West Coast and most of the South, such as Texas, Louisiana, Mississippi, Alabama, Georgia, and the Carolinas.

When to Plant: Mid-March

Common Plants:

Strawberry tree (Arbutus unedo)
Mexican orange (Choisya temata)
Hibiscus (Hibiscusselections)
New Zealand daisy-bush (Olearia haastii)
Japanese pittosporum (Pittosporum tobira)
Cherry-laurel (Prunus laurocerasus)
Texas mountain laurel (Sophora secundiflora)
Laurustinus (Viburnum tinus)
Yucca (Yuccaselections)

Zone 9: 20 to 30°F

It's pure California dreaming with hot and heavy temperatures hitting this zone. These plants can withstand temperatures as low as 20 to 30°F but thrive in 70-90° temperatures. You can find Zone 9 consuming California's landscape, along with Southern Texas, Louisiana, and Florida.

When to Plant: Mid-February

Common Plants:

Asparagus fern (Asparagus setaceous)
Dahlia (Dahlia selections)
Tasmanian blue gum (Eucalyptus globulus)
Fuchsia (Fuchsia selections)
Silk-oak (Grevillea robusta)
Sweetshade tree (Hymenosporum flavum)
California pepper tree(Schinus molle)
Australian bush cherry (Syzygium paniculatum)

Zone 10: 30 to 40°F

Zone 10 sees some of the hottest temperatures in the U.S., prevalent in tropical places such as Southern California and Southern Florida. Plants in this zone can handle temperatures as low as 30 to 40°F.

When to Plant: Mid-January

Common Plants:

Bougainvillea (Bougainvillea spectabilis)
Golden shower (Cassia fistula)
Ensete (Ensete ventricosum)
Lemon eucalyptus (Eucalyptus citriodora)
Rubber plant (Ficus elastica)
Violet churcu (Iochroma cyaneum)
Royal palm (Roystonea regia)
Palmetto palm tree (Sabal spp.)

Zone 11: 40 to 50°F

Tropical plants flourish in Zone 11, which covers Hawaii. This zone enjoys year-round heat, and plants can withstand temperatures above 40 to 50°F. There is no frost whatsoever, and native plants thrive throughout the whole year.

When to Plant: Any time

Common Plants:

Lime (Citrus aurantiifolia)
Sago palm (Cycas revoluta)
Grevillea (Grevillea)