Zone 9 11 plants

How to Use Hardiness Zone Information

Gardeners need a way to compare their garden climates with the climate their plant is known to grow well. That’s why the hardiness zones were created. USDA hardiness zones are used to indicate where various permanent landscape plants can adapt. If you want a shrub, perennial, or tree to survive and grow year after year, the plant must tolerate year-round conditions in your area, such as the lowest and highest temperatures and the amount and distribution of rainfall.

The familiar plant zone map on the back of many seed packet is visual representation of the system. Seed packet maps are based on the USDA Plant Hardiness Zone Map, which was originated by the U.S. Department of Agriculture and overseen by the National Arboretum.

The USDA Plant Hardiness Zone Map is one of several plant zone maps developed to provide this critical climate information. The USDA plant zone map is the one most gardeners in the eastern United States rely on, and the one that most national garden magazines, catalogs, books, and many nurseries currently use. This map divides North America into 11 separate zones. Each plant hardy zone is 10 degrees F warmer (or colder) in an average winter than the adjacent zone. (In some versions of the map, each zone is further divided into “a” and “b” regions.)

The USDA zone map does a fine job of delineating the garden climates of the eastern half of North America. That 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.

Problems with the Zones

Image zoom

Although a good guide for many gardeners, the USDA zone map is not perfect. In the eastern half of the country, the USDA zone map doesn’t account for the beneficial effect of a snow cover over perennial plants, the regularity or absence of freeze-thaw cycles, or soil drainage during cold periods. And in the rest of the country (west of the 100th meridian, which runs roughly through the middle of North and South Dakota and down through Texas west of Laredo), the USDA zone map fails.

Many factors beside winter lows, such as elevation and precipitation, determine growing climates in the West. Weather comes in from the Pacific Ocean and gradually becomes less marine (humid) and more continental (drier) as it moves over and around mountain range after mountain range. While cities in similar gardening zones in the East can have similar climates and grow similar plants, in the West it varies greatly. For example, the weather and plants in low-elevation, coastal Seattle are much different from those in high-elevation, inland Tucson, Arizona, even though they’re in the same Zone (USDA Zone 8).

The Zones

Each USDA Zone in the system represents a region of minimum average winter temperatures. The lower the USDA Zone number, the colder the region. Although factors other than temperature affect the ability of a plant to survive, the USDA Zone system is a reasonable starting point for many gardeners.

The chart below shows the temperature ranges associated with the Zone system. In this chart, the USDA garden Zones are divided into A and B regions, which are sometimes used to fine-tune plant recommendations.

Zone Minimum Temperature Example Cities 1 Below -50 F Fairbanks, Alaska; Resolute, Northwest Territories (Canada) 2a -50 to -45 F Prudhoe Bay, Alaska; Flin Flon, Manitoba (Canada) 2b -45 to -40 F Unalakleet, Alaska; Pinecreek, Minnesota 3a -40 to -35 F International Falls, Minnesota; St. Michael, Alaska 3b -35 to -30 F Tomahawk, Wisconsin; Sidney, Montana 4a -30 to -25 F Minneapolis/St.Paul, Minnesota; Lewistown, Montana 4b -25 to -20 F Northwood, Iowa; Nebraska 5a -20 to -15 F Des Moines, Iowa; Illinois 5b -15 to -10 F Columbia, Missouri; Mansfield, Pennsylvania 6a -10 to -5 F St. Louis, Missouri; Lebanon, Pennsylvania 6b -5 to 0 F McMinnville, Tennessee; Branson, Missouri 7a 0 to 5 F Oklahoma City, Oklahoma; South Boston, Virginia 7b 5 to 10 F Little Rock, Arkansas; Griffin, Georgia 8a 10 to 15 F Tifton, Georgia; Dallas, Texas 8b 15 to 20 F Austin, Texas; Gainesville, Florida 9a 20 to 25 F Houston, Texas; St. Augustine, Florida 9b 25 to 30 F Brownsville, Texas; Fort Pierce, Florida 10a 30 to 35 F Naples, Florida; Victorville, California 10b 35 to 40 F Miami, Florida; Coral Gables, Florida 11 above 40 F Honolulu, Hawaii; Mazatlan, Mexico

The plants listed below provide examples of the coldest USDA garden Zones in which specific plants will survive. In this list, only the coldest USDA Zone is considered; some of the plants listed will not 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 degrees F

Image zoom

  • 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 degrees F

Image zoom

  • 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 3: -40 to -30 degrees F

Image zoom

  • Common juniper (Junipercus communis)
  • Japanese bayberry (Berberis thunbergii)
  • Russian olive (Elaeagnus angustifolia)
  • Tatarian honeysuckle (Lonicera tatarica)
  • Siberian crabapple (Malus baccata)
  • American arborvitae (Thuia occidentalis)

Zone 4: -30 to -20 degrees F

Image zoom

  • Sugar maple (Acer saccharum)
  • Panicle hydrangea (Hydrangea paniculata)
  • Chinese juniper (Juniperus chinensis)
  • Amur River privet (Ligustrum amurense)
  • Virginia creeper (Parthenocissus quinquefolia)
  • Vanhouffe spirea (Spiraea x vanhouttei)

Zone 5: -20 to -10 degrees F

Image zoom

  • Flowering dogwood (Cornus florida)
  • Slender deutzia (Deutzia gracilis)
  • Common privet (Ligustrum vulgare)
  • Boston ivy (Parthenocissus tricuspidata)
  • Japanese rose (Rosa multiflora)
  • Japanese yew (Taxus cuspidata)

Zone 6: -10 to 0 degrees F

Image zoom ‘Bloodgood’ Japanese maple

  • Japanese maple (Acer palmatum)
  • Common boxwood (Buxus sempervirens)
  • Winter creeper (Euonymus follunei )
  • English ivy (Hedera helix)
  • American holly (Ilex opaca)
  • California privet (Ligustrum ovalifolium)

Zone 7: 0 to 10 degrees F

Image zoom

  • Bigleaf maple (Acer macrophyllum)
  • Kurume azalea (Rhododendron Kurume hybrids)
  • Atlas cedar (Cedrus atlantica)
  • Small-leaf cotoneaster (Cotoneaster microphylla)
  • English holly (Ilex aquifolium)
  • English yew (Taxus baccata)

Zone 8: 10 to 20 degrees F

Image zoom

  • Strawberry tree (Arbutus unedo)
  • Mexican orange (Choisya temata)
  • New Zealand daisy-bush (Olearia haastii)
  • Japanese pittosporum (Pittosporum tobira)
  • Cherry-laurel (Prunus laurocerasus)
  • Laurustinus (Viburnum tinus)

Zone 9: 20 to 30 degrees F

Image zoom

  • Asparagus fern (Asparagus setaceous)
  • Tasmanian blue gum (Eucalyptus globulus)
  • Australian bush cherry (Syzygium paniculatum)
  • Fuchsia (Fuchsia hybrids)
  • Silk-oak (Grevillea robusta)
  • California pepper tree (Schinus molle)

Zone 10: 30 to 40 degrees F

Image zoom

  • Bougainvillea (Bougainvillea spectabilis)
  • Golden shower (Cassia fistula)
  • Lemon eucalyptus (Eucalyptus citriodora)
  • Rubber plant (Ficus elastica)
  • Ensete (Ensete ventricosum)
  • Royal palm (Roystonea regia)

Welcome to the
Plant Hardiness Zone Map of the British Isles.

The plant hardiness zone map of the British Isles is the most detailed ever to be created for this region, and is the product of many months work studying the average winter climate statistics for the periods 1961 to 2000 recorded by the Irish and UK Met Offices.

The USA first undertook climatic studies to provide a guide map for plant hardiness of the North American continent. These were undertaken by two independent groups: The Arnold Arboretum of Harvard University in Cambridge, Massachusetts, and the United States Department of Agriculture (USDA) in Washington, D.C. See the USDA map.

When we took it upon ourselves to create the Plant Hardiness Zone Map of the British Isles we replicated the same zones, based on the same equivalent temperature scale as the USA to form a basic standardisation. However, we have changed the colour coding for the 7 split zones occurring in the British Isles to colours which are more meaningful to the average user.

Both our map and the USDA maps are inadequate due to factors such as the frequency and duration of cold outbreaks. The main problem is the fact that the British Isles lies so far north of the equator, where both winter and winter nights are long. No other place on the planet, which shares similar winter temperatures is situated so far from the equator, and therefore our problems are quite unique. The noticeable differences are to be seen in our zones 10a & 9b. Whereas, plants from other country’s zones 10a & 9b can whithstand short, colder outbreaks than us and survive, in the British Isles they must endure a winter which is several months long with low light levels and wet weather. Consequently, there are very few plants, labelled as zone 9 or 10 that can be grown here.
It is important to understand that average minimum air temperatures (protected from wind & direct sun) are used in defining these zones. Ambient temperatures will be lowered by local frost pockets and by wind-chill. Although, plants do not suffer from the effects of wind-chill like we do, they can get dehydrated and suffer from windburn in cold easterly winds. Therefore, you must read these zones as the maximum potential temperature for an area once windbreaks have been put in place. For example – If you see from the map that you are in a potential zone 9a then you can over winter plants outdoors, which are suitable for zones 8b, 8a, 7b etc. You will only be able to over winter plants suitable for zone 9a once protection has been put in place and a favourable microclimate created.

Essential reading: Predicting Cold Hardiness in Palms Trebrown Blog.

2010-2013 Update

We had plans for an updated Plant Hardiness Zone Map of the British Isles, and many months work had already gone into this by 2011. The general trend had been a period of increased warming over the decade since we first published the map. However, the British Isles were then hit by two successively cold winters and a third not quite so cold but nevertheless colder than we had been used to. The results of these cold spells has been to bring the pattern of the map back similar to what it was. There are only slight pattern changes from the original map, and for this reason we have decided to save work and retain the original map without an update, as this is the best match for the British Isles without any temporary warming patterns which may be misleading.

Growing Recommendations for Zone 10b

I am looking for suggestions for plants for my garden in Florida. I do not reside there and need something that requires little care and attention, such as watering, pruning, etc.

Advertisement

Hardiness Zone: 10b

By Louise from Ocala, FL

Answers:

By kathleen williams

If you plant native things you’ll have plants that require less care. Look around the area. In zone 10 you can grow almost anything. You should try living in zone 4. Everything freezes. (04/26/2009)

By Judi

Since you do not reside here, invest in colorful low maintenance perennials. Here’s a few suggestions:
Trees- Dogwood and Crape Myrtle. Shrubs – Azalea, Gardenia, Hardy Hibiscus, Hydrangea, Bridal Wreath Spirea, and Camellia. Plants and Bulbs – Day Lily, Hosta, Iris, Dwarf Canna, Plumbago and Bush Jasmine. Avoid plants with thorns. Avoid vines such as Wisteria and Trumpet vine that will grow out of control during your absence.

Advertisement
(04/27/2009)

By Donna

If you have any shady areas Calladiums grow excellently here as do ferns, there are many varieties and some with neat colors. Bromelliads do well here, as well. Another plant I love and think does really well here is Shrimp plant and it comes in a few different colors. African Iris, Agapanthus, and Ficus do very well, too. (04/27/2009)

By abigail chamberlain

Best Plants for a Cottage Garden

Rustic and Casual

Photo by Jerry Pavia

Casual cottage gardens play host to everything from afternoon naps on a hammock to lantern-lit dinners. Inviting front gardens with loosely designed flower beds and rambling paths can channel a rustic charm that extends to the backyard entertaining area. Whether you’re looking for showstopping color or something a little more muted to blend in as a backdrop, its important to choose the right plants. To bridge the barrier between outdoors and in, we’ve chosen plants worth your while.

Hollyhocks

Photo by John Glover/Alamy

(Alcea rosea)

Butterflies and hummingbirds flock to this old-fashioned favorite, which is well suited for growing along walls and fences. Tall, sturdy stems support purple, pink, white, or yellow flowers. ‘Chater’s Double Hybrid’ bears double flowers from early to midsummer, in shades of red, apricot, and yellow against rounded, light-green leaves.

Grows 6 to 8 feet tall and 18 to 24 inches wide in USDA Hardiness Zones 3 to 9; full sun.

Hydrangea

Photo by Courtesy of Missouri Botanical Garden

(Hydrangea aborescens)

Known for its dazzling flower heads that can reach 6 inches wide, this species was voted one of the 75 greatest plants for gardens by the American Horticultural Society. ‘Annabelle’ bears massive 12-inch-diameter rounded clusters of white flowers over medium green, pointed leaves; blooms from June to September.

Grows 3 to 5 feet tall and 4 to 6 feet wide in USDA Hardiness Zones 4 to 9; partial shade.

Catmint

Photo by Courtesy of Missouri Botanical Garden

(Nepeta racemosa)

It’s noted for its appeal to cats, but this low-maintenance plant has a more practical use—it repels mosquitoes. Aromatic gray-green leaves are set against two-lipped flowers in violet to lilac blue. Easy-to-grow ‘Walker’s Low’ is drought resistant and tolerates rocky soil, producing trumpet-shaped, deep violet and lilac-blue flowers from April to September.

Grows 24 to 30 inches tall and 30 to 36 inches wide in USDA Hardiness Zones 4 to 8; sun to part shade.

Sage

Photo by Courtesy of Missouri Botanical Garden

(Salvia x sylvestris)

S. Sylvestris is a hybrid with half-inch-long pinkish flowers that form a thick clump atop rigid stems with scalloped leaves. ‘Mainacht,’ also called ‘May Night,’ has dense shoots of deep purple flowers that tower high above foliage from May to June and work well with pink-flowering plants.

Grows 18 to 24 inches tall and 12 to 18 inches wide in USDA Hardiness Zones 5 to 9; full sun.

Coneflower

Photo by Courtesy of Missouri Botanical Garden

(Echinacea purpurea)

During the summer months, the stems bear purplish flowers with daisy-like, droopy petals; but come winter, its stiff, cone-like center attracts a wide range of birds. ‘Bright Star,’ also known as ‘Leuchstern,’ is one of the faster-growing cultivars with bright rose to lavender-pink blooms up to 12 inches wide from June to August.

Grows 30 to 48 inches tall and 12 to 18 inches wide in USDA Hardiness Zones 3 to 9; full sun to partial shade.

Garden Phlox

Photo by Courtesy of Missouri Botanical Garden

(Phlox paniculata)

Despite its 4-foot height, this fast-growing perennial rarely needs staking to support the fragrant 1-inch-wide white or pale- to dark-lilac flowers. For a particularly long growing season choose ‘Eva Cullum,’ a slightly shorter cultivar with fragrant pink flowers and slightly darker centers over green leaves in pyramidal clusters from July to September.

Grows 24 to 30 inches tall and wide in USDA Hardiness Zones 4 to 8; full sun to partial shade.

Bleeding Heart

Photo by Courtesy of Missouri Botanical Garden

(Lamprocapnos spectabilis)

Whimsical bleeding heart is an elaborate, old-time species that stands out among shade-loving plants. Named after the heart-shaped pink flowers fringed with white petals, which dangle from its arching stems and soft-green foliage in late spring and early summer.

Grows 24 to 36 inches tall and 18 to 30 inches wide in USDA Hardiness Zones 3 to 9; part to full shade.

Delphinium

Photo by Courtesy of Walters Gardens

(Delphinium grandiflorum)

Though short-lived, blooming only from June to July, when D. grandiflorum comes around it puts on a display of rich blue, violet, or white flowers on stalks up to 20 inches high, perfect for plush borders or edging. Unlike many cultivars of this species, dwarf ‘Summer Nights’ sits lower to the ground and flowers from early to late summer with indigo-blue flowers on lacy mid-green foliage.

Grows up to 10 to 12 inches tall and wide in USDA Hardiness Zones 3 to 8; full sun to partial shade.

Sundrops

Photo by Courtesy of Missouri Botanical Garden

(Oenothera fruticosa)

A member of the late-evening-blooming primrose family, sundrops has yellow, cup-shaped flowers up to 2 inches wide that open during the day from late spring deep into summer. For an interesting display of contrasting colors choose ‘Fyrverkeri,’ also known as ‘Fireworks,’ which bears bright-yellow saucer-shaped flowers from red buds over reddish stems and green to purplish foliage.

Grows 12 to 18 inches tall and 12 to 24 inches wide in USDA Hardiness Zones 4 to 8; full sun.

Lady’s Mantle

Photo by Courtesy of Missouri Botanical Garden

(Alchemilla mollis)

Great for groundcover because of its 6-inch-long light-green leaves, this clump-forming species also produces tiny star-shaped bunches of chartreuse flowers from early summer to early autumn. The lobed leaves retain showy moisture beads after a rainy day.

Grows 12 to 18 inches tall and 18 to 30 inches wide in USDA Hardiness Zones 4 to 7; full sun to partial shade.

Peony

Photo by Courtesy of Missouri Botanical Garden

(Paeonia lactiflora)

Synonymous with cottage-garden design, peonies are old-fashioned plants with big, impressive blooms and a wide range of color options. P. lactiflora has splashed of red on the stems and single cup-shaped white to pale-pink flowers up to 4 inches in diameter. ‘Duchesse de Nemours’ flowers for about 10 days in May and June, but after the creamy-white double flowers fall away, the dark-green foliage remains attractive through early fall.

Grows 30 to 36 inches tall and wide in USDA Hardiness Zones 3 to 8; full sun or part shade.

Shasta Daisy

Photo by Courtesy of Missouri Botanical Garden

(Leucanthemum x superbum)

No staking is required for the 36-inch-tall, rigid stems that bear these coarse yellow disks rimmed with vibrant white petals. For color from July to September try ‘Becky,’ which grows taller than other cultivars but has slightly smaller 3- to 4-inch flower heads over medium-green lance-shaped leaves.

Grows 3 to 4 feet tall and 2 to 3 feet wide in USDA Hardiness Zones 5 to 9; full sun.

Sweet Pepperbush

Photo by Courtesy of Missouri Botanical Garden

(Clethra alnifolia)

The late-summer-blooming C. alnifolia shrub bears fragrant, bell-shaped white flowers unti early September, with leaves turning an attractive yellow in fall. ‘Ruby Spice’ is a great cultivar with fragrant pink flowers shaped like a bottlebrush and serrated, waxy green leaves; tolerates moist soil—perfect for poorly draining areas.

Grows 4 to 6 feet tall and 3 to 5 feet wide in USDA Hardiness Zones 4 to 8; sun to part shade.

Foxglove

Photo by Courtesy of Missouri Botanical Garden

(Digitalis purpurea)

Another old-time garden favorite that resembles gloves with the fingers snipped off. D. purpurea’s tall stalks in early summer of 2½- to 3-inch-long purple, pink, or white flowers are puckered at the ends and have hairy foliage that can be dark green or white-wooly.

Grows 3 to 6 feet tall and 1 to 2 feet wide in USDA Hardiness Zones 4 to 8; full sun to part shade.

Snapdragon

Photo by Courtesy of Missouri Botanical Garden

(Antirrhinum majus)

This oldie bears spikes filled with fragrant two-lipped flowers ranging in color from yellows and whites to purples and pinks. Often grown as an annual, snapdragons prefer cooler growing conditions, where they’ll produce an abundance of glossy green leaves and richly shaded or bicolored blossoms from April through the first frost. A. majus’s cultivars range from taller plants to fill in mixed borders to intermediate ones for bedding to dwarfs for containers or edging.

Grows 12 to 72 inches tall and 6 to 24 inches wide in USDA Hardiness Zones 9 to 11; full sun.

Coral Bells

Photo by Courtesy of Missouri Botanical Garden

(Heuchera villosa)

Native to the rocky slopes of the Appalachian mountains, this species makes for great edging along walkways. The 3½- to 18-inch-long panicles usually have white flowers tipped with green and broad, lance shape petals. ‘Autumn Bride’ has especially toothy light-green leaves grow in soft triangles amid white blooms from August to September.

Grows 18 to 36 inches tall and 18 to 24 inches wide in USDA Hardiness Zones 3 to 8; part shade to full sun.

Bee Balm

Photo by Courtesy of www.perennialresource.com

(Monarda didyma)

Ovate, mid-green leaves grow up to 5½ inches long on square stems to showcase a flower with single or double whorls of pink or red petals. ‘Raspberry Wine’ has flower buds shaped like summer berries, with blooms that resemble spiky purple-red tubes from early summer to early fall.

Grows 32 to 42 inches tall and wide in USDA Hardiness Zones 4 to 9; full sun to part shade.

Mock Orange

Photo by Ulf/Commons.Wikimedia.org

(Philadelphus ‘Belle Etoile’)

Nicknamed for its resemblance to orange blossoms, ‘Belle Etoile,’ a flowering shrub, has cupped, very fragrant white flowers with blotchy, pale-purple centers. They grow singularly on stems or as clusters of three to five and are paired with tapered, narrow leaves from May to June.

Grows 5 to 6 feet tall and 3 to 4 feet wide in USDA Hardiness Zones 5 to 8; full sun to part shade.

Rose of Sharon

Photo by Courtesy of Monrovia

(Hibiscus syriacus)

A cottage-garden favorite, this species is a shrub covered in large, trumpet-shaped dark-pink flowers and toothy dark-green leaves from June to October. ‘Sugar Tip,’ sometimes also called ‘American Irene Scott,’ bears light-pink double flowers and uniquely streaked white-and-blue-green foliage in a cultivar that holds up well to humidity, drought, and poor soil.

Grows 8 to 12 feet high and 4 to 6 feet wide in USDA Hardiness Zones 5 to 8; full sun to part shade.

Large Coneflower

Photo by Courtesy of Missouri Botanical Garden

(Rudbeckia maxima)

Petals are often the focal point of a great flower, but R. maxima is known for its towering dark-brown central cones that measure from 2 to 6 inches high. The cylindrical-shaped centers are rimmed with slightly droopy yellow petals and sit above cupped gray-green leaves. Blooms from June to July.

Grows 5 to 6 feet tall and 3 to 4 feet wide in USDA Hardiness Zones 4 to 8; full sun.

Tickseed

Photo by Courtesy of www.perennialresource.com

(Coreopsis grandiflora)

Often grown as an annual, the hairless stems on this species let the flower take center stage. The 3- to 5-inch-diameter gold to yellow flowers bloom from late spring to late summer. Rich-yellow ‘Early Sunrise’ has semi-double flowers with splotchy orange-yellow centers from May to August.

Grows 18 to 24 inches tall and wide in USDA Hardiness Zones 4 to 9; full sun.

Siberian Iris

Photo by Courtesy of www.perennialresource.com

(Iris sibirica)

Deliciously blue-violet petals paired with medium-green grasslike foliage. Groups of up to five flowers blossom in early spring to early summer. Easy-to-maintain ‘Strawberry Fair’ features large, ruffled magenta blooms with variegated centers in shades of blue and white that will awe.

Grows 20 to 28 inches tall and 18 to 24 inches wide in USDA Hardiness Zones 3 to 9; full sun to part shade.

Goatsbeard

Photo by Courtesy of Missouri Botanical Garden

(Aruncus dioicus)

Goatsbeard’s rich green fern-like foliage bursts with tiny clustered flowers in pale creams, yellows, and greens. The 20-inch-long flower clusters bloom from early to midsummer and can resemble astilbe.

Grows 4 to 6 feet tall and 2 to 4 feet wide in USDA Hardiness Zones 3 to 7; full sun to part shade.

True Geranium

Photo by Courtesy of Monrovia

(Geranium cinereum)

A dwarf variety of the cranesbill geranium is an evergreen with gray-green leaves and translucent, cup-shaped white or pink flowers in late spring to early summer. ‘Ballerina’ has darker, grayer leaves than the species, with flowers that range from purple to red with dark veining.

Grows 6 to 8 inches high and 12 to 15 inches wide in USDA Hardiness Zones 5 to 9; full to partial sun.

‘Miss Kim’ Lilac

Photo by Courtesy of Monrovia

(Syringa pubescens subsp. patula ‘Miss Kim’)

This mound-forming shrub has spikes filled with sweet-smelling, pale-lilac-blue flowers in May, with dark-green foliage that often turns purple in fall.

Grows 4 to 9 feet tall and 5 to 7 feet wide in USDA Hardiness Zones 3 to 8; full sun.

‘Joseph’s Coat’ Rose

Photo by Courtesy of Monrovia

(Rosa ‘Joseph’s Coat’)

Roses, in nearly any form, are the backbone of an informal cottage garden. ‘Joseph’s Coat’ is a vigorous climbing or shrub rose with bunches of cupped yellow flowers that age to orange and pink after blooming from spring to fall.

Grows 8 to 12 feet tall and 5 to 8 feet wide in USDA Hardiness Zones 6 to 9; full sun.

‘Climbing Cecile Brunner’ Rose

Photo by Courtesy of Monrovia

(Rosa ‘Climbing Cecile Brunner’)

A strong grower with lance-shaped, dark-green leaves. Starting in early summer, it bears groupings of fragrant, soft light-pink flowers.

Grows 8 to 20 feet tall and 3 to 6 feet wide in USDA Hardiness Zones 5 to 9; full sun to part shade.

Zoning in on Hardiness

Learn how to determine if a plant will act as an annual or perennial in your area. Learn what USDA hardiness zones are and how they can help you have a better garden.

One of the most commonly asked questions by gardeners has to be “Is this plant an annual or a perennial?” This deceptively simple question is a bit more complicated than it sounds. Perennials are generally described as plants that return year after year without replanting. Whether a plant is a perennial or an annual is based on whether that plant can withstand the cold temperatures of winter.

This sounds simple and in some ways it is simple. The main factor complicating things is that winter temperatures vary widely across North America. In an effort to help gardeners understand which plants are hardy in which areas the USDA developed and published a plant hardiness zone map. This map was first published in 1960. It was updated in 1965 and again in 1990.

This USDA Plant Hardiness Zone Map divides the US and Canada into 11 different zones. These zones are based on the lowest average temperature each area is expected to receive during the winter. The averages used to develop the current map are based on winter temperatures from 1974 through 1986.

The first step in accurately predicting whether a plant will be hardy for you is to find out what your USDA hardiness zone is. If you don’t know your zone you can use the U.S. Hardiness Zone Finder to learn what zone you live in or use this map for Canadian zones. This finder allows you to type in your zip code and it will tell you what zone you live in.

Once you know which zone you live in, it is relatively easy to figure out whether a plant will be perennial or annual. Simply compare your zone to the zone or zones listed on the plant tag or website or within a gardening book.

If your zone is equal to or higher than the zone listed for the plant it will be hardy for you, it is perennial in your area. An example, I live in zone 5. If the plant tag says a plant is hardy in zones 5 to 9 the plant will be perennial for me. It would also be perennial in zone 6, 7, 8, and 9. If the plant tag says a plant is hardy to zone 4 then the plant will be perennial for me.

If your zone is lower than the zone listed on the tag then the plant will not be hardy for you, it is an annual in your area. An example, if the plant tag says a plant is hardy in zones 6 to 10 the plant will be an annual for me in zone 5.

The same zones that apply to annuals or perennials also apply to shrubs and trees.

Once you know what zone you live in and understand a bit about how hardiness zones work, deciding whether a plant is likely to act as a perennial and survive your winter becomes much easier.

There are some other things to consider as far as hardiness goes.

  1. The hardiness zone map assumes that the plant will be planted in the ground not in a raised pot or window box. The ground (soil) remains slightly warmer and won’t freeze as solid as a raised pot will. The pot will frequently thaw out from time to time even in the winter. It is this thawing and re-freezing that will cause many perennials and even some woody shrubs to be less hardy in a container than the landscape. The zones listed in catalogs and on tags and websites refers to the zone a plant is hardy to if planted in the ground. If you are planting in a pot you will need to choose plants that are two zones hardier than the one you live in. So for me to have a plant hardy in a pot it would need to be hardy to at least zone 3 rather than zone 5.
    You could also dig a hole in your vegetable garden or an out of the way spot in your garden. Place the pot into this hole and fill in soil until it is level with the lip of the pot. This will keep your pot as warm as the surrounding ground helping the plant within the pot survive the winter.
  2. Plant breeders are constantly working to select plants that are hardier than the regular species. It is possible that a newer, named cultivar could be hardier than the regular species.
    That being said, it is also possible that a newer, named cultivar is less hardy than the regular species. This will sometimes happen when a new flower or leaf color (or pattern) is discovered. Sometimes these genetic breakthroughs are initially linked with less hardy plants. So if a plant tag lists a zone that is either hardier or less hardy than the general species it isn’t necessarily a mistake.
  3. It is also sometimes possible to take a plant that is one zone less hardy than your zone and bring it through the winter. If you live in zone 5, a zone 6 plant could be perennial for you. There are several reasons this could be true. First the published zone information might be incorrect. Second, it is often possible to find spots within your garden or even within your community that stay a few degrees warmer than the rest of the general area. For instance, areas that are protected from the wind are often warmer. Areas next to your house, especially south facing exposures, or those near a brick or stone wall can retain more warmth also.

The moisture level, how well your soil drains, how much you mulch, when you mulch, and how much snow cover you have can all affect whether a plant is perennial or not. Many plants that should be hardy will suffer in soils that don’t drain well. Thick layers of mulch, properly applied, can increase hardiness as can a thick, insulating layer of snow. The changing weather conditions each year can allow some plant to ‘perennialize’ for a few years and yet we all know that sooner or later, the real climatic zone will catch up with the hardy annual.

What does this all mean to you? Hardiness zones are essential information for choosing which plants are likely to be perennial, however, by experimenting with placement and plants that are almost perennial, it is possible to expand the selection of plants that are perennial in your garden.

Ask a Question or Give Feedback about this article. 513 Readers Rated This: 12345 (3.1)

What to Plant When in Your Locality

USA Hardiness Zone 10a

Planting Calendar & Monthly Lists

Scroll to Map & Zone Description
See the Sowing Calendar
Download the Sowing Calendar

Planting List

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NOTE: No Planting in Winter Months.

USA Zone 10a

Extreme Minimum Temperate −1.1 to +1.7°C (30 to 35°F)

Temperate Year Round, Warm Winters and Hot Summers
Indicative Towns: Naples, Florida; Victorville, California

This Zone covers Southern inland California, southern Florida and parts of inland Hawaii. The lack of frosts and freezing temperatures provides a huge boost for winter gardening. However the extreme heat of the summer limits planting possibilities during the hot months.

Cool season crops, such as lettuces, peas and radishes can be grown during the winter with low risk of cold damage. Summer vegetables must tolerate the hot summer days and frequent watering is required. Shifting vegetables into shaded areas also helps. Some extra varieties to consider are: Peanuts, Malabar spinach, Taro, Bitter melon, Tomatillos, Ginger, Curry leaf and Miracle fruit.

Towns Include:

Alameda, California
Albany, California
Belle Glade, Florida
Berkeley, California
Bonita, California
Brownsville, Texas
Burbank, California
Californiape Coral, Florida
Cape Coral, Florida
Carlsbad, California
Chino, California
Chino Hills, California
Chula Vista, California
Clearwater, Florida
El Cajon, California
El Monte, California
Encino, California
Escondido, California
Estero, Florida
Fontana, California
Fort Myers, Florida
Hacienda Heights, California
Hayward, California
Hobe Sound, Florida
Irvine, California
Jurupa Valley, California
La Habra, California
La Puente, California
Laguna Niguel, California
Lake Forest, California
Lehigh Acres, Florida
Naples, Florida
North Fort Myers, Florida
Oceanside, California
Ontario, California
Oxnard, California
Pacoima, California
Panorama City, California
Pasadena, California
Pinole, California
Pomona, California
Port Saint Lucie, Florida
Port St. Lucie, Florida
Punta Gorda, Florida
Rancho Cucamonga, California
Reseda, California
Rialto, California
Rosemead, California
Safety Harbor, Florida
San Diego, California
San Francisco, California
San Mateo, California
Santa Barbara, California
Santa Rosa, California
Sarasota, Florida
South San Francisco, California
Spring Valley, California
St. Petersburg, Florida
Sunland, California
Surprise, Arizona
Thousand Oaks, California
Union City, California
Van Nuys, California
Ventura, California
Vero Beach, Florida
West Covina, California
West Palm Beach, Florida
Whittier, California

Disclaimer: The PlantWhatWhen vegetable planting guide is only designed for use as a very general reference for home gardening purposes. It is not to be used for farming, markets or commercial activities of any kind whatsoever. We take absolutely no responsibility for the accuracy and adequacy of the information provided on this site. We recommend that you consider your local climate, weather patterns and conditions when deciding what and when to plant in your home garden. It’s entirely your own decision. Happy Gardening and Best Wishes!

Leave a Reply

Your email address will not be published. Required fields are marked *