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This blog post is all about the USDA planting zones. The United States Department of Agriculture (USDA) has designated specific zones for certain areas in North America that are best suited to different types of plants.
This article will cover what each zone means, as well as some other considerations you should take into account before deciding which zone you want your garden to be planted in.
During the mid-1900s, the US Department of Agriculture introduced plant zones for North Americana and Mexico. 13 USDA plant zones cover the entire US including Puerto Rico, Alaska, and Hawaii.
Zone 1 begins with Alaska that registers bitter cold winters from as low as -600F to zone 13 which has tropical temperatures of not lower than 600F in some parts of Hawaii.
A plant associated with a lower plant zone number means that the plant can tolerate colder temperatures and still live and flourish.
As the name suggests, planting zones are specific areas that you can locate on a growing zone map that exactly shows you the plants that are most suited to do well in a given zone.
The associated terms, ‘plant hardiness zones’ and ‘growing zones’ could at first seem somewhat confusing when you go shopping for plants for your garden. For many years now, growers use plant hardiness zones to identify what plants are highly likely to survive wintertime in their area.
It is vital to understand hardiness zones so that you have a guide for making prudent planting decisions.
The term plant hardiness refers to the ability of any plant to survive severe growing climates like cold, drought, heat, and flooding. The science behind it can be complicated but a major factor that determines a plant’s ability to withstand extremes of temperature without damage is plants genetics.
Depending on the adaptations and genetics, every cultivator of plants may have varying hardiness levels. Different parts of plants can be hardy in numerous ways. For instance, the cold could cause your perennial to die but the roots may still be hardy enough to allow for new growth in the spring.
Several plants need specific growing environments to flourish. It is easier to adjust the soil type, amount of sunlight, and moisture levels in your garden but the temperature is hard to control.
For the best chance of landscaping and gardening success, settle for the plants with hardiness levels appropriate to certain planting zones.
Understanding the Plant hardiness zones
In the end, USDA hardiness zones safeguard a grower in Alaska from making an error of planting the wrong sort of plants that won’t grow.
When you understand the different plant hardiness zones, it will give you the ability to choose your gardening choices. Remember that when a plant is hardy to a particular zone, it will also thrive at a zone number that is higher too.
Most plants that can survive in zone 3 are also able to thrive in zone 7 if other plant requirements are satisfied.
Planting zone 1
As mentioned, zone 1 expects a minimum average temperature ranging from -60 to 50 degrees Fahrenheit, zone 1a expects a minimum average temperature ranging from -60 to 55 degrees Fahrenheit, zone 1b has a minimum average temperature ranging from -55 to 50 degrees Fahrenheit.
Each of the two subzones will experience harsher temperatures depending on existing weather conditions.
Plants to grow in zone 1
It is quite a challenge to cultivate in planting zone 1 because the plants that can withstand tundra are so rare.
An excellent choice is settling for natural plants like native plants since they have adapted to the area. Another popular option is annuals because they don’t need to survive the winter.
However, native perennials that are suitable for zone 1 are relatively few but with proper planting and care, they can flourish.
Because most vegetables are annuals, you don’t need to worry as much about their cold tolerance as much as the length of the growing season. To increase the success of zone 1 veggies, provide them with a head start in a greenhouse or at home.
Some of the popular zone 1 vegetables include kale, broccoli, cabbage, beans, potatoes, lettuce, sweet peas, spinach, tomatoes, radish, and tomatoes.
Not very many fruit trees are hardy enough to survive the extreme cold of zone 1 but with the right conditions, the following fruits can thrive: Fort mac apple, chokecherry, September ruby apple, and haskap.
Almost every herb to grow in planting zone 1 can be grown as an annual and they include Mint, Basil, Chives, Rosemary, Oregano, ad thyme.
Flowers need to be cold hardy and drought tolerant; the most popular flower choices are the Delphinium, Yarrow, Sunflower, Goldenrod, Arrowhead, oxeye daisy, and lily of the valley.
Planting zone 2
Planting zone 2 is in both the continental United States and Alaska. It has average minimum temperatures of -50 to 40 degrees Fahrenheit.
The temperatures can be challenging to many gardeners because drought conditions and high winds are found both in the tundra and plains found in zone 2.
What gives gardeners a growing advantage are creative planting techniques for planting annuals and native plants.
Plants to grow in zone 2
The plants in zone 2 should at all times be able to withstand high levels of drought and extreme cold.
Most native plants are best adapted to this type of environment. Annuals are a good choice for this zone; some perennials too can thrive when chosen carefully.
The most suitable vegetables to grow in plant zone 2 are those with short growing seasons.
Few perennial vegetables can withstand such extremely cold temperatures in zone 2 like the asparagus. Consider planting mustard greens, carrots, onions, Swiss chard, parsnips.
Fruits to grow in zone 2 include parkland apple, Brook gold plum, fofonoff plum, fall red apple, Garrington chokecherry, norkent apple, Korean pine, Minnesota 1734 apple, Pembina plum, parkland apple.
Annual herbs are excellent in zone whether they are self-sowing plants or replanted. Herbs to consider include Turkestan rose, hyssop, juniper, poppy, bleeding heart, penstemon, monkshood, violet, sea holly, and primrose.
Planting zone 3
The zone, which can be found throughout Alaska, in high-altitude regions of the United States, and northern portions of Canada, comprises average minimum temperatures ranging from -40 to -30 degrees Fahrenheit.
Low moisture, extreme cold, and high winds affect the growing conditions depending on the geographical location.
Plants to grow in zone 3
Vegetables to grow in zone 3 include cucumbers, asparagus, celery, winter squash, and summer squash.
For fruit trees that grow in zone 3, they include Evans cherry, Cupid cherry, Goodland apple, early gold pear, Dolgo crabapple, Golden spice pear, Westcot apricot, Toka plum, sweet sixteen apples, and Waneta plum.
For the herbs, pick annual herbs or any other in this list: Garlic, Caraway, Parsley, Catnip, French sorrel, Horseradish, English chamomile, and peppermint.
There are several flowers hardy enough to withstand temperatures in zone 3 and they include Salvia, Aster, Liatris varieties, Blanket flower, Alpine Rockcress, spurge, Snow-in-summer, wallflower, and Virginia bluebells.
Planting zone 4
This zone covers high elevations in the western mountains, the northern areas of the United States, and the southern coastal areas of Alaska.
The average temperatures range from a minimum of -30 to -20 degrees Fahrenheit and planting in this zone is notably less challenging compared to colder zones.
However, short growing seasons impacts both flower bloom times and vegetables.
Plants to grow in zone 4
Add the following vegetables to your plant garden: melons, eggplant, pumpkins, and okra.
Numerous cold hardy fruit trees thrive in planting zone 4 like Trent apple, nova pear, butternut, railroad apple, alderman plum, butternut, alexander apple, summer crisp pear, and the Ewing blue plum.
For most herbs to grow in zone 4, they require the application of mulch during winter. Plants like the Angelica, thyme, lemon balm, bee balm, mountain mint, garden sage, and winter savory.
If you want to grow flowers in zone 4, you can plant iris, phlox, caneflower, iris, daylily, plantain lily.
Planting zone 5
Zone 5 spans across the north-central United States, southern coastal regions of Alaska, and some parts of New England.
Minimum average temperatures range from -20 to -10 degrees Fahrenheit and this zone has moderately cool winters. Since the growing season is short, extend it by using started plants in the annual garden or using cold frames.
Plants to grow in zone 5
Vegetables to grow in zone 5 include lettuce, kale, spinach, radishes, and winter greens.
Fruit trees to grow in zone 5 include superior plum, native pawpaw trees, snow beauty peach, pink lady apple, Honeycrisp apple, and the warren pear. For herbs, grow hybrid mints, lavender, and the large-flowered calamint.
Perennial flowers to grow are black-eyed Susan, baptisia, cinquefoil, campanula, and Russian sage.
Planting zone 6
Hardiness zone 6 covers a lot of the United States: it is one of the biggest planting zones. The climate is generally mild and the average temperatures range from a minimum of -10 to 0 degrees Fahrenheit.
There are many growing options in zone 6 featuring cold winter and mild-to-hot summers.
Plants to grow in zone 6
There are many plants suitable for landscaping and gardening. The options are countless for nurseries, seed companies, and garden centers.
Vegetables that will do well are winter squash, bush beans, longer-season melons, butter lettuce, and intermediate tomatoes. Fruit trees are Loring, Jefferson, late Crawford, red globe, nectar, and Madison.
For herbs, settle for those that reseed themselves Dill, Borage, Coriander, oregano, and false chamomile. Available flowers will bloom for many months like snapdragons, pansies, lady’s mantle, flowering fern, Japanese bottlebrush, floribunda rose, and sedum.
Planting zone 7
The zone spans 15 states. In the zone, the winters are cool and there is a range of temperatures from 0 to 10 degrees Fahrenheit.
Gardens have multiple plant options from local home stores, seed catalogs, greenhouses, and nurseries.
Plants to grow in zone 7
Vegetables are Hot peppers, Arugula, sweet peppers, turnips, and long growing season vegetables.
Fruit trees to grow are the Fuji apple, bing cherry, Cortland apple, blue java pineapple, contender peach, Ozark plum, Fuyu persimmon, red gold nectarine, granny smith apple, rainier sweet cherry, Moorpark apricot, parker pear, scout apricot, turkey fig, Stella cherry, and a wide variety of elderberries, mulberries, and pawpaw trees.
Herbs to grow in zone 7 include sage, feverfew, rue, tarragon, and marjoram. Flowers to grow in zone 7 are candytuft, clematis, butterfly weed, forget-me-not, chrysanthemum, peony, four o’clock, and painted daisies.
Planting zone 8
This zone is the warmest in the southern US and includes most of Texas. It’s minimum temperature is 10 degrees Fahrenheit and goes to 20 degrees.
Growers enjoy a long planting season with mild winters and hot summers.
Plants to grow in zone 8
Most gardeners in this zone grow vegetables three times every year with the aid of row covers and cold frames.
The vegetables include cantaloupe, okra, field peas, bolt-resistant lettuce varieties, hot peppers, tomatoes, and watermelon.
Fruit trees are Alma fig, bronze banana, abaca banana, Anna apple, Bryan apricot, Darjeeling banana, clementine tangerine, Meyer lemon, jujube varieties, gala apple, kumquat and limequat varieties, marsh grapefruit, ruby grapefruit, Montmorency cherry, Washington orange, multiple varieties of plums and peaches.
Herbs to grow are mostly native to Mediterranean areas and thrive in long and hot summers.
Most are also drought-resistant and include Mexican oregano, sage, bay laurel, rosemary, and marjoram.
Flowers to grow are lantana, Asiatic lily, Mexican petunia, hardy geranium, and phlox.
Planting zone 9
This zone is a year-round planting zone. Arizona, Florida,Texas, California, along the Gulf of Mexico coast. The zone features hot summers and warm winters.
The average minimum temperatures during the winter range from 20 to 30 degrees Fahrenheit and the zone has active gardens all through the year.
Plants to grow in zone 9
The heat is more of an issue because of long and hot summers. Only tropical plants that have low water requirements can thrive in zone 9.
You will be likely to grow the following vegetables through the winter: cauliflower, broccoli, spinach, cabbage, greens, and Brussel sprouts. Fruit trees in zone 9 are olives, giant pomelo, avocado, hardy kiwi, calamondin, passionfruit, mandarin orange, trifoliate orange, and star fruit.
Herbs to grow in zone 9 are those that tolerate heat and they include chives, mint, basil, lemon thyme, bay laurel, marjoram, and coriander.
Flowers in zone 9 showcase blooms throughout the year. They include canna, zinnia, dahlia, hydrangea, black-eyed Susan, wisteria, rhododendrons.
Planting zone 10
Zone 10 gardeners can avoid freezing temperatures and this is a huge advantage in winter gardening although the extreme heat of summer months will limit planting possibilities.
Hawaii, southern Florida, and southern inland California are the three areas where average winter temperatures range from a minimum of 30 to 40 degrees Fahrenheit.
Plants to grow in zone 10
The plants to thrive in zone 10 are tropical plants. It is hot and humid, and there are not many frosty days. The frost is a big concern.
Include these vegetables in your zone 10 garden: peanuts, bitter melon, jicama, tomatillos, and Malabar spinach.
Many exotic fruit trees are ideal in zone 10 like the apple guava, allspice tree, Carica papaya, June plum, dwarf Cavendish banana, jackfruit tree, and the soursop tree.
Herbs that grow in zone 10 are ginger, curry leaf, miracle fruit, galangal, and the Mexican tarragon.
For flowers, beautiful additions to the flower garden include agave, aeoniums, African lily, Peruvian lily, floss flower, delta maidenhair fern, geraniums, ornamental onion, hummingbird mint, and various aloes.
Plant zone 11
Plant zone 11 is a very warm area that includes mild winters with an average minimum winter temperature of 40 to 50 degrees Fahrenheit and occasional subfreezing temperatures. It may be found on Puerto Rico, Hawaii, the Florida Keys, and certain regions of the continental United States.
Cold hardiness is never a factor for this zone because it has no frost days. Growers in this zone need to consider the impact heat will have on their planting choices.
Zone 11 experiences minimum average temperatures ranging from 40 to 50 degrees Fahrenheit. Expect average temperatures ranging from 40 to 45 degrees Fahrenheit in zone 11a.
In Zone 11, the average minimum temperature is approximately 45 to 50 degrees Fahrenheit. Depending on the weather conditions, both subzones may have harsher temperatures.
Plants to grow in zone 11
Zone 11 is the best for tropical plants. With warm winters and long and hot summers, growers in this zone need to settle for highly heat-tolerant plants.
The cold season plants like pansies and spinach will both have limited growing seasons even in the coolest part of winter here.
Plants that are from the same area as the place where they will live have a better chance of living well in hot weather.
Gardening happens throughout the year with temperature determining the rotation of plants.
Some cool-season vegetables suitable for winter gardening are beets, kale, carrots, cabbage, Swiss chard, radishes, sweet peas.
Fruit trees to grow in zone 11: most tropical and citrus fruits thrive in zone 11 and the exotic choices include mango, jaboticaba, sea grape, macadamia, natal plum, and moringa tree.
The extreme heat of summer makes it difficult to grow herbs in zone 11. Many won’t produce seeds because of the heat so they should be planted as annuals in cooler months.
Some herbs that you can start planting during early spring include thyme, basil, chives, mint, lemongrass, Mexican oregano.
Many cool-season flowers can thrive in mild winters of zone 11, with no danger of frost, however the blooms generally perish due to excessive summer temperatures.
Flowers able to take in the long and hot summers in zone 11 are ponytail palm, kangaroo paw, anemone coronaria, bougainvillea, begonias, and drumstick allium.
Planting zones 12 and 13
Plant zones 12 and 13 are in Puerto Rico and Hawaii. They are not in the continental United States.
The two plant hardiness zones are most suitable for plants tolerant to intense heat since both zones are extremely warm with tropical environments. The average winter temperature is between 50 and 70 degrees.
The warmest of all USDA hardiness zones, zones 12 and 13 have exotic fruits and tropical plants.
Expect a minimum average temperature of 50 to 60 degrees Fahrenheit for zone 12.
Zone 12a has a minimum average temperature ranging from 50 to 55 degrees Fahrenheit and zone 12b has an average temperature ranging from 55 to 60 degrees Fahrenheit.
For zone 13, temperatures are between 60-70 degrees Fahrenheit.
Zone 13a experiences a minimum average temperature ranging from 60 to 65 degrees Fahrenheit while the minimum average temperature in zone 13b ranges from 65 to 70 degrees Fahrenheit.
The same thing can happen in both zone 12 and 13. The temperature can change if the weather changes.
Plants to grow in zone 12 and 13
People need to be careful about how much heat they give plants. In zones 12 and 13, make sure the temperatures stay at a level that is not too hot.
The key to successful landscaping and gardening in the extreme heat of both zones is tropical plants. Growers purchase plants, from nurseries, germinate indoors or grow several vegetables during cooler winter months.
Vegetables to grow in zones 12 and 13.
In zones 12 and 13, there’s no shortage of produce. It is advisable to plant during cooler months and irrigate or use shade to reduce heat.
Plant summer vegetables earlier so you can harvest them in late June or early July.
Late summer monsoon seasons mostly bring relief from the intense heat and provide better conditions for another chance to plant.
Settle for plants that are drought and heat tolerant and which have a short growing season too. Such vegetables include hot pepper, tomatoes, bush beans, summer squashes, and eggplant.
Fruit trees to grow in both zones are Alupaq, African apricot, ackee, African breadfruit, imbe, amazon tree-grape, tropical almond, black pepper, bacuri cascudo, java olive, and bignay.
The herbs to grow in zones 12 and 13 need plenty of moisture and planning. Make sure to look for heat tolerant options like sage, borage, rosemary, cilantro, savory, and cilantro.
Flowers to grow in zones 12 and 13 bloom beautifully in the hot climate with proper care. Plant flowers from the following tropical families heliconia, Cannaceae, Musaceae, Cactaceae, Strelitziaceae, Lamiaceae, Marantaceae, Zingiberaceae.
No matter the zone you live in, ensure you have watering equipment.