COLORADO (CO)
How To Use Our Interactive Hardiness Zone Map
Use the tool we’ve attached above to find your Planting Zone by zip code plus some tips to help you out in the garden.
- Type in your Zip Code and State. When you click ‘enter’, your Hardiness Zone will be shown at the top left of the search box.
- Once you have your zone, you can navigate to the corresponding section below to see the lowest Winter temperatures, estimated first and last frost dates, list of plants you can grow, and other helpful facts about your Zone.
- You will also see a floating information box about your State. If you click on “More Info”, you’ll be taken to another page where you can read about the basic growing conditions in your State. We’ve prepared listicles with pictures to help you choose the best trees to grow in your area!
Understanding USA Plant Hardiness Zones
What is a Hardiness Zone?
Also called: Growing Zone, Gardening Zone, Planting Zone, Plant Hardiness Zone
The Hardiness Map was developed by the United States Department of Agriculture to categorize the country into 13 zones based on their average lowest Winter temperatures.
Using this information, gardeners can select plants that are most likely to survive the intensity of Winters in their area. Whether you’re shopping for plants online or in local nurseries, you’ll find that each plant is tagged with a specific zone range!
Please note that there are separate Hardiness Maps developed for Canada, Australia, and Europe. If you’re in America, always look for a “USDA” label when checking a plant’s cold hardiness.
Do you really need to know your Hardiness Zone as a gardener?
Most plants can only tolerate up to a specific degree of chill. Knowing your Hardiness Zone means you can focus your time, attention, and money on plants with the best chance of survival in the Winter.
As a rule of thumb, a plant that is hardy to Zone 1 will also be hardy to Zones 2, 3 and the next few higher zones. Of course, nothing is set in stone when it comes gardening! Nature always finds a way, so treat the zones more like a guideline than a rule book.
Limitations of the Hardiness Zone Map
Zone information by itself cannot 100% predict the Winter survivability of trees, shrubs, and other greenery. You’ll have to consider other factors that can affect the health of your plants:
- Summer temperatures, length of growing season
- Average frost dates, snow cover
- Precipitation
- Soil drainage, soil fertility
- Quality of plant specimens, management practices
The 2012 USDA Plant Hardiness Zone Map
The 2012 USDA Hardiness Zone Map takes into account the 48 conterminous states of America, plus Alaska, Hawaii, and Puerto Rico. Zone 1 is found in the coldest and northernmost areas of Alaska, while Zone 13 is in the warmest and southernmost parts of Hawaii.
This map is based on weather data collected from 1976-2005. Each zone is based on the 30-year average of the single coldest temperature recorded each Winter. Divided into 13 zones calibrated at 10°F intervals, every zone is further split into subzones “a” and “b”.
USDA Planting Zone 1
USDA Zone 1 covers only a few parts of Alaska. Its two subzones can experience harsher temperatures depending on weather conditions.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 1 | -60 to -50 °F | -51 to -46 °C |
| Zone 1a | -60 to -55 °F | -51 to -48 °C |
| Zone 1b | -55 to -50 °F | -48 to -46 °C |
Gardening is a serious challenge for people who live in Zone 1. For your plants to thrive in this zone, you may need to provide them with heavy Winter mulch, supplemental water, and sheltered locations like greenhouses.
Trees for Zone 1: Boxelder, Common Hackberry, Green Ash, Lombardy Poplar, Peachleaf Willow, Plains Cottonwood, Siberian Crabapple
Vegetables for Zone 1: Beans, Broccoli, Cabbage, Kale, Lettuce, Potato, Radish, Spinach, Sweet Pea, Tomato
Herbs for Zone 1: Basil, Catnip, Chive, Cilantro, Dill, Fennel, Mint, Oregano, Rosemary, Thyme
Flowers for Zone 1: Arrowhead, Delphinium, Goldenrod, Lily of the Valley, Oxeye Daisy, Sunflower, Yarrow
USDA Planting Zone 2
USDA Zone 2 is also found mostly in the interior areas of Alaska, but the Winter temperatures aren’t as low as they are in Zone 1.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 2 | -50 to -40 °F | -46 to -40 °C |
| Zone 2a | -50 to -45 °F | -46 to -43 °C |
| Zone 2b | -45 to -40 °F | -43 to -40 °C |
Gardening in Zone 2, you’ll need to deal with a tundra-like environment, frequent drought, and a short growing season lasting only 3 months. To make things easier, you can start seeds indoors, apply mulch to plants, and use cold frames.
Trees for Zone 2: Black Cottonwood, Colorado Blue Spruce, Golden Willow, Rocky Mountain Maple, Scotch Pine, White Poplar
Vegetables for Zone 2: Beans, Beets, Cabbage, Carrot, Echinacea, Ginseng, Goldenseal, Mustard Greens, Onion, Parsnip, Swiss Chard, Valerian
Herbs for Zone 2: Ginseng, Goldenseal, Hyssop, Juniper, Lavender, Turkestan Rose
Flowers for Zone 2: Bleeding Heart, Monkshood, Penstemon, Poppy, Primrose, Sea Holly, Violet
USDA Planting Zone 3
USDA Zone 3 is found in the northernmost portions and high-altitude areas of the USA. It includes Alaska, Colorado, Idaho (3b only), Maine (3b only), Minnesota, Montana, New Hampshire, New York (3b only), North Dakota, South Dakota (3b only), Vermont (3b only), Wisconsin (3b only), and Wyoming.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 3 | -40 to -30 °F | -40 to -34°C |
| Zone 3a | -40 to -35 °F | -40 to -37 °C |
| Zone 3b | -35 to -30 °F | -37 to -34 °C |
Expect high winds, low soil temperatures, and low moisture in the Winter if you’re gardening in Zone 3. Luckily, scientists have been breeding and selecting cold-hardy trees for decades, so there’s plenty of options to plant in Zone 3.
Trees for Zone 3: Cottonwood, Eastern White Pine, European Dogwood, Hackberry Tree, Honeylocust, Norway Spruce, Youngstown Juniper
Vegetables for Zone 3: Asparagus, Celery, Cucumber, Romaine, Summer Squash, Tomato, Winter Squash
Herbs for Zone 3: Caraway, Catnip, English Chamomile, French Sorrel, Garlic, Horseradish, Parsley, Peppermint
Flowers for Zone 3: Alpine Rockcress, Aster, Blanket Flower, Liatris, Salvia, Snow-in-Summer, Spurge, Virginia Bluebells, Wallflower
USDA Planting Zone 4
USDA Zone 4 ranges from coastal areas in Alaska to high elevations in the Western regions. Other states included are Arizona (4b only), Colorado, Idaho, Iowa (4b only), Maine, Michigan, Minnesota, Montana, Nebraska, Nevada, New Hampshire, New Mexico (4b only), New York, North Dakota, Oregon (4b only), South Dakota, Utah, Vermont, Washington, Wisconsin, and Wyoming.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 4 | -30 to -20 °F | -34 to -29 °C |
| Zone 4a | -30 to -25 °F | -34 to -32 °C |
| Zone 4b | -25 to -20 °F | -32 to -29 °C |
Gardening in Zone 4 isn’t as challenging as it is in colder zones, but you will still have to deal with a short growing season that can impact flowering and fruiting cycles. It might be a good idea to start seeds indoors, or purchase vegetable starters from garden centers to give you a headstart.
Trees for Zone 4: Bald Cypress, Crabapple Tree, Douglas Fir, Newport Plum, Pin Oak, Redbud Tree, Saucer Magnolia
Vegetables for Zone 4: Asparagus, Beet, Carrots, Chard, Lettuce, Mustard, Onion, Parsnip, Peas, Potato, Radish, Spinach, Turnip
Herbs for Zone 4: Angelica, Bee Balm, Garden Sage, Lemon Balm, Mountain Mint, Thyme, Winter Savory
Flowers for Zone 4: Aster, Coneflower, Crocus, Daffodil, Delphiniums, Hibiscus, Hostas, Hyacinth, Peonies, Phlox, Sedum, Tulips, Yarrow
USDA Planting Zone 5
USDA Zone 5 includes Alaska, Arizona, California, Colorado, Connecticut (5b only), Idaho, Illinois, Indiana (5b only), Iowa, Kansas (5b only), Maine, Maryland (5b only), Massachusetts, Michigan, Minnesota (5a only), Missouri (5b only), Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, North Carolina (5b only), Ohio (5b only), Oregon, Pennsylvania, South Dakota, Tennessee (5b only), Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 5 | -20 to -10 °F | -29 to -23 °C |
| Zone 5a | -20 to -15 °F | -29 to -26 °C |
| Zone 5b | -15 to -10 °F | -26 to -23 °C |
Zone 5 has moderate Winters and mild Summers. The short growing season lasts from Late Spring to Mid Fall. To keep the soil warm a little longer, you can make use of raised beds, hoop tunnels, and cold frames.
Trees for Zone 5: Autumn Brilliance Serviceberry, Cherry Trees, Chinese Fringe Tree, Cleveland Select Pear, Dwarf Red Buckeye, Emerald Green Arborvitae, Snow Beauty Peach
Vegetables for Zone 5: Asparagus, Beets, Broccoli, Kale, Lettuce, Radish, Spinach, Winter Greens
Herbs for Zone 5: Cilantro, Chives, Coriander, Dill, Lavender, Mint, Oregano, Parsley, Sage, Thyme
Flowers for Zone 5: Baptisia, Black-eyed Susan, Campanula, Cinquefoil, Daylily, Delphinium, Phlox, Rudbeckia, Russian Sage
USDA Planting Zone 6
USDA Zone 6 spans from Alaska, Arizona, Arkansas (6b only), California, Colorado, Connecticut, Georgia, Idaho, Illinois, Indiana, Iowa (6a only), Kansas, Kentucky, Maine (6a only), Maryland, Massachusetts, Michigan, Missouri, Montana (6a only), Nevada, New Hampshire (6a only), New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island (6a only), Tennessee, Texas (6b only), Utah, Virginia, Washington, West Virginia, to Wyoming (6a only).
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 6 | -10 to 0 °F | -23 to -18 °C |
| Zone 6a | -10 to -5 °F | -23 to -21 °C |
| Zone 6b | -5 to 0 °F | -21 to -18 °C |
With Winters that aren’t too cold and Summers that aren’t too hot, Zone 6 offers a wide selection of plants for gardeners. You may still need to start seeds indoors, but you can enjoy a long, productive growing season outdoors from Early Spring to Early Fall.
Trees for Zone 6: Amur Maple, Austrian Pine, European Mountain Ash, Ginkgo Biloba, Leyland Cypress, Paperbark Cherry, Red Dogwood, Tri-Color Beech
Vegetables for Zone 6: Bush Beans, Indeterminate Tomatoes, Lettuce, Longer-season Melons, Winter Squash
Herbs for Zone 6: Borage, Catnip, Chamomile, Coriander, Dill, Marjoram, Oregano, Rosemary
Flowers for Zone 6: False Sunflower, Floribunda Rose, Flowering Fern, Japanese Bottlebrush, Lady’s Mantle, Sedum
USDA Planting Zone 7
USDA Zone 7 covers Alaska, Alabama, Arizona, Arkansas, California, Colorado (7a only), Connecticut (7a only), Delaware, Georgia, Idaho, Illinois (7a only), Kansas (7a only), Kentucky (7a only), Maryland, Massachusetts, Mississippi (7b only), Missouri, Nevada, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island (7a only), South Carolina, Tennessee, Texas, Utah, Virginia, Washington, and West Virginia.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 7 | 0 to 10 °F | -18 to -12 °C |
| Zone 7a | 0 to 5 °F | -18 to -15 °C |
| Zone 7b | 5 to 10 °F | -15 to -12 °C |
If you’re in Zone 7, you can enjoy mild climates and a gardening period of about 8 months. The important thing to consider is the shift in seasons. Just because a plant can survive Winter in Zone 7, that doesn’t automatically mean it can tolerate full sun in the Summer.
Trees for Zone 7: Apricot Tree, Austrian Pine, English Holly, Hydrangea Shrubs, Juniper ‘Wichita Blue’, Plum Trees, Shumard Oak Tree
Vegetables for Zone 7: Beets, Broccoli, Cabbage, Carrot, Collards, Kale, Lettuce, Peas, Potato, Radish, Spinach, Sweet Pepper, Turnip
Herbs for Zone 7: Arugula, Chives, Feverfew, French Lavender, Marjoram, Oregano, Rosemary, Rue, Sage, Tarragon, Thyme
Flowers for Zone 7: Butterfly Weed, Candytuft, Chrysanthemum, Clematis, Forget-me-not, Four O’clock, Painted Daisy, Peony
USDA Planting Zone 8
USDA Zone 8 includes Alaska, Alabama, Arizona, Arkansas (8a only), California, Florida, Georgia, Louisiana, Maryland (8a only), Mississippi, Nevada, New Mexico, North Carolina, Oklahoma (8a only), Oregon, South Carolina, Tennessee (8a only), Texas, Utah, Virginia (8a only), and Washington.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 8 | 10 to 20 °F | -12 to -7 °C |
| Zone 8a | 10 to 15 °F | -12 to -9 °C |
| Zone 8b | 15 to 20 °F | -9 to -7 °C |
In Zone 8, Summers are hot and Winters are mild. There’s plenty of evergreen trees, shrubs, and perennial flowers for you to grow year-round. You may need to water your plants more often in the Summer.
Trees for Zone 8: Crape Myrtle, Hemlock, Sequoia, Honeylocust, Ironwood, Korean Boxwood, Oak Tree, Pecan Tree, Pindo Palm, Strawberry Tree, Walnut Tree
Vegetables for Zone 8: Lettuce, Cantaloupe, Chamomile, Field Peas, Hot Pepper, Okra, Tomato, Watermelon
Herbs for Zone 8: Basil,Bay Laurel, Lavender, Marjoram, Mexican Oregano, Mint, Rosemary, Sage
Flowers for Zone 8: Asiatic Lily, Dahlias, Geraniums, Hibiscus, Lantana, Mexican Petunia, Phlox, Salvia, Yarrow
USDA Planting Zone 9
USDA Zone 9 encompasses Alabama (9a only), Arizona, California, Florida, Georgia (9a only), Hawaii, Louisiana, Mississippi (9a only), Nevada, New Mexico (9a only), Oregon, South Carolina (9a only), Texas, Utah (9a only), and Washington (9a only).
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 9 | 20 to 30 °F | -7 to -1 °C |
| Zone 9a | 20 to 25 °F | -7 to -4 °C |
| Zone 9b | 25 to 30 °F | -4 to -1 °C |
You can garden all year-round in Zone 9, but hot dry summers can be a problem for many plants. Even the Winters are relatively warm, so avoid plants that require a long period of dormancy before blooming. Make sure to choose drought-tolerant and heat-tolerant varieties.
Trees for Zone 9: Black Walnut, Citrus Trees, Crape Myrtle, Deodar Cedar, Leyland Cypress, Peach Tree, Purple Orchid Tree, Red Dogwood, Weeping Willow
Vegetables for Zone 9: Broccoli, Brussel Sprouts, Cabbage, Cauliflower, Greens, Spinach
Herbs for Zone 9: Basil, Bay laurel, Chives, Coriander, Lemon Thyme, Marjoram, Mint
Flowers for Zone 9: Black-eyed Susan, Canna, Dahlia, Hydrangea, Rhododendron, Wisteria, Zinnia
USDA Planting Zone 10
USDA Zone 10 comprises Arizona, California, Florida, Hawaii, Louisiana (10a only), Nevada (10a only), and Texas (10a only). This zone features warm temperatures and humid conditions throughout most of the year.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 10 | 30 to 40 °F | -1 to 4 °C |
| Zone 10a | 30 to 35 °F | -1 to 2 °C |
| Zone 10b | 35 to 40 °F | 2 to 4 °C |
If you’re a gardener in Zone 10, setting up a chore calendar may be the most important thing to do. You can grow vegetables and herbs all year round, but you’ll have to plan when to sow seeds according to their different harvest periods and heat tolerance.
Trees for Zone 10: Banana Tree, Eucalyptus Tree, Muscogee Crape Myrtle, Royal Empress, Sago Palm
Vegetables for Zone 10: Bitter Melon, Jicama, Malabar Spinach, Peanuts, Tomatillos
Herbs for Zone 10: Curry Leaf, Galangal, Ginger, Mexican Tarragon, Miracle Fruit
Flowers for Zone 10: Aeonium, Agave, African Lily, Floss Flower, Geranium, Hummingbird Mint, Ornamental Onion, Peruvian Lily
USDA Planting Zone 11
USDA Zone 11 is found in California (11a only), Florida (11a only), and Hawaii. In these regions, Winters are mellow while Summers are extremely warm.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 11 | 40 to 50 °F | 4 to 10 °C |
| Zone 11a | 40 to 45 °F | 4 to 7 °C |
| Zone 11b | 45 to 50 °F | 7 to 10 °C |
Cold-hardiness is not a factor for plants in Zone 11 because there is no frost. Instead, you might want to look up a Heat Zone Map. It divides the country into 12 zones based on the number of days wherein the temperature goes above 86°F in each region.
Trees for Zone 11: Citrus Trees, Desert Ironwood, Kiwi, Mexican Palo Verde, Paurotis Palm, Sweet Acacia
Vegetables for Zone 11: Beet, Cabbage, Carrot, Kale, Radish, Sweet Pea, Swiss Chard
Herbs for Zone 11: Basil, Chives, Lemongrass, Mexican Oregano, Mint, Thyme, Turmeric
Flowers for Zone 11: Begonia, Dahlia, Impatiens, Kangaroo Paw, Passionflower, Peace Lily, Petunia
USDA Planting Zone 12
USDA Zone 12 is not found within the continental United States, but instead includes the warm and humid islands of Hawaii and Puerto Rico.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 12 | 50 to 60 °F | 10 to 16 °C |
| Zone 12a | 50 to 55 °F | 10 to 13 °C |
| Zone 12b | 55 to 60 °F | 13 to 16 °C |
Tropical plants and exotic fruit trees grow in Zone 12. Extreme heat and drought are a real challenge for gardeners, so the growing season is cut in half by the full Summer sun.
Trees for Zone 12: Avocado Tree, Bamboo, Coconut Tree, Mango Tree, Palm Tree, Weeping Fig
Vegetables for Zone 12: Bush Beans, Carrot, Chili Pepper, Cilantro, Cucumber, Eggplant, Lettuce, Pak Choi, Radish, Spinach, Sweet Potato, Tomato, Watermelon, Yam
Herbs for Zone 12: Basil, Borage, Cinnamon, Dill, Marjoram, Mint, Nutmeg, Rosemary, Sage, Savory, Thyme
Flowers for Zone 12: Amaryllis, Anthurium, Begonia, Jasmine, Desert Willow, Hibiscus, Ivy Geranium, Lantana, Moth Orchid, Oleander, Plumeria, Portulaca, Scarlet Sage
USDA Planting Zone 13
USDA Zone 13 is the warmest region in the USA, located in the state of Hawaii (13a only) and the territory of Puerto Rico. Subzone 13b can only be found in a tiny part of Puerto Rico.
| Minimum Average Temperatures | ||
|---|---|---|
| Zone 13 | 60 to 70 °F | 16 to 21 °C |
| Zone 13a | 60 to 65 °F | 16 to 18 °C |
| Zone 13b | 65 to 70 °F | 18 to 21 °C |
Human population may be small in Zone 13, but it’s home to a diverse variety of exotic flora. To contend with extreme temperatures and little rainfall in the Summer, farmers in Zone 13 use shade nets and irrigation lines, or wait for the cooler seasons before planting crops.
Trees for Zone 13: Bamboo, Banana Tree, Orchid Tree, Palm Tree
Vegetables for Zone 13: Bush Beans, Eggplant, Hot Pepper, Summer Squashes, Tomato
Herbs for Zone 13: Anise, Basil, Borage, Cilantro, Culantro, Licorice, Rosemary, Sage, Savory
Flowers for Zone 13: Aloe, Amaryllis, Anthurium, Dahlia, Daisy, Heliconia, Hibiscus, Lantana, Lotus, Petunia, Plumeria, Zinnia
