Plant Hardiness Zones - Important Information for Gardening Success

USDA Hardiness Zone Map
Find your Growing Zone
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Zones are sometimes subdivided into a colder half (a) and a warmer half (b): for example 5a or 7b
 

There are thousands of plant varieties that will grow for U.S. gardeners but not all plants will thrive in all areas of our vast country.

While tropical plants may be happy in Florida gardens, they'll likely freeze and die in Chicago winters. Likewise, peonies and tulips, plants that require winter cold to flourish, will thrive in parts of the country with freezing winter temperatures but won't in the Deep South. How do you know which plants will work in your region?

Hardiness Zones were developed to support informed decisions. Each region has been assigned a zone; just use the map above to select your region or alternatively you can use our Zone Finder (input your Zip Code to the left) to determine yours.

With this information, look for plants that list your hardiness zone on the product page and after the word "Hardiness:". So, if you garden in zone 6, plants with hardiness ratings that include zone 6 (zones 3-8 or zones 6-10) should thrive in your climate year round.

Tip: Gardeners sometimes fall in love with plants that aren't hardy in their region. Must broken hearts follow? No, but the plants in question will need special attention. Suppose you love freesia but don't live in zones 9-11 where these tender beauties are hardy. To have multi-season success with freesia you'll have to over winter them in a warm place like a heated greenhouse or on your windowsill. Alternately, you may treat them as annuals; enjoying their blooms the first season and replacing them next year, like you do with petunias. This is the easiest approach and a successful way to fool Mother Nature for one season.

 

    Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10  
Alliums Alliums X X X X X X X   Alliums grow in a wide variety of climates; check specific cultivars for zone hardiness.
Amaryllis Amaryllis           X X X All amaryllis grow only in warmer zones outdoors but can be grown indoors anywhere.
Anemones Anemones     X X X X X X For the most winter hardy anemones choose Blanda Mix. Others are hardy in zones 7-10.
Astilbes Astilbes X X X X X X X   Excellent winter hardy and heat tolerant plant suitable for most parts of the country.
Babiana Babiana           X X X Babiana are South African plants that thrive in warm, dry Mediterranean climates.
Bearded Iris Bearded Iris X X X X X X X X Bearded iris vary widely as far as climate preference; see individual product listings.
Belladonna Lilies Belladonna Lilies         X X X X Belladonnas like hot, dry weather and are winter hardy to zone 7 with mulch.
Bleeding Hearts Bleeding Hearts X X X X X X X   Hardiness varies; bleeding hearts will thrive in intense cold but not extreme dryness.
Callas Callas         X X X X Winter hardiness varies by cultivar in zones 6 and 7 but all varieties thrive in warmer areas.
Calochortus Calochortus         X X X X All varieties are winter hardy as far north as zone 7; for zone 6 choose Golden Orb or Venustus.
Camassia Camassia   X X X X X X X Happy in a wide range of temperatures, most camassia prefer a somewhat moist setting.
Chionodoxa Chionodoxa (Glory of the Snow) X X X X X X X   Easy to please, Glory of the Snow (Chinodoxia) cultivars are hardy in almost all areas of the U.S.
Crocus Crocus X X X X X X     Early, easy, inexpensive and colorful; crocuses are popular for many good reasons.
Daffodils Daffodils (Narcissus) X X X X X X X X Daffodil cultivars (probably many) for every growing zone; check specifics listed with individual varieties.
Daylilies Daylilies X X X X X X X   There's a daylily cultivar (or many) for every growing zone; check specifics for individual varieties.
    Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10  
Dutch Iris Dutch Iris     X X X X X   Preferring moderate to warm climates, Dutch iris vary in hardiness; check cultivar listings.
Foxtail Lilies Foxtail Lilies (Eremurus)       X X X X   Eremurus is happiest in moderate to warm climates and thrives in average to dry environments.
Freesia Freesia             X X Freesia prefer warm sites; they are not winter hardy in areas colder than zone 9.
Fritillaria Fritillaria X X X X X X X   With a variety of forms and native regions, Fritillaria zones vary; check individual variety listings.
Garlic & Shallots Garlic & Shallots   X X X X X     Garlic and shallots thrive in most zones in well-drained, nutritious soil. Mulch to protect against wide temperature swings.
Geraniums Geraniums (hardy)   X X X X X X   Winter hardy geraniums come back year after year in most of the country; see individual listings.
Grape Hyacinths Grape Hyacinths X X X X X X X X Very winter hardy and able to manage hot areas, grape hyacinths will grow in most of the country. See cultivar listings.
Hostas Hostas X X X X X X X   With cultivars for every zone, hostas can be grown across the country. Check zone information for each variety.
Hyacinths Hyacinths   X X X X X     All our hyacinths are winter hardy in cold regions and will return year after year in zones 4-8.
Ixia Ixia           X X X Ixia is not winter hardy in cold areas; will return year after year outdoors in warm zones 8-10.
Japanese Iris Japanese Iris   X X X X X X   Winter hardy from zones 4 or 5 (see individual listings) through 9, These grow in most of the US.
Leucojum Leucojum   X X X X X X X Easy to please leucojum provide cheery, fragrant spring blooms, naturalizing readily in most parts of the U.S.
Lilies Lilies X X X X X X X   Stately, striking and rich with spicy scents, trumpet lilies grow across a wide variety of zones.
Lycoris Lycoris       X X X X X All these thrive in the warm zones 8 through 10. For zones 6-7, mulch is required.
Ornithogalum Ornithogalum     X X X X X X All these thrive in the warm zone 9 & 10; cold hardiness varies. Check individual listings.
    Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10  
Oxalis Oxalis   X X X X X X X For greatest cold hardiness choose Adenophylla; the others prefer zones 8-10. Grow indoors anywhere in good sunlight.
Paperwhites Paperwhites           X X X Primarily grown indoors where zone information is irrelevant. Requires the warm weather of zones 8-10 outside.
Peonies Peonies X X X X X       Garden royalty with big blooms, killer fragrance, & live 50+ years. Only able to grow and flower in cool climates.
Plumeria Plumeria             X X Plumeria need lots of sun and warmth, but surprisingly little water. Rapidly draining soil is a must. Protect from frost.
Ranunculus Ranunculus           X X X Ranunculus are hardy in 8-10 but can be grown as annuals (in spring) in cooler areas. Start before weather turns hot.
Saffron Crocus Saffron Crocus     X X X X     Lots of sun, well-drained soil, a cold winter and a hot, dry summer dormancy yield the best results with saffron crocus.
Scilla Scilla   X X X X X X X Heat and cold tolerance varies by cultivar; see individual listings.
Shallots Shallots X X X X X X X X Shallots thrive in most zones in well-drained, nutritious soil. Apply thick winter mulch in zones colder than 6.
Siberian Iris Siberian Iris X X X X X X X   Happily adapting to most climates, Siberian Iris are not suited to hot, dry climates
Snowdrops Snowdrops X X X X X X X   Snowdrops are very cold hardy (zone 3) and manage up to zone 9 heat; see individual listings.
Spanish Bluebells Hyacinthoides Spanish Bluebells X X X X X X     Comfortably surviving very cold winters, Spanish Bluebells grow well as far south as zone 8.
Sparaxis Sparaxis           X X X Sparaxis require warm settings; they are not winter hardy in areas colder than zone 8.
Squill Giant White Squill, Giant White           X X X Giant White Squill survives in moderate zone 8; loves hot zones 9 and 10. Likes dry settings.
Tulips Tulips X X X X X X X   Species tulips are very cold tolerant; they can also manage dry heat, as far south as zone 9. Check individual variety listings.
Watsonia Watsonia         X X X X Watsonia cultivars are hardy from zones 7 or 8 through 10; check individual variety listings.
    Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10  


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