Hardy gardenia zone 6

Cold Hardy Gardenias – Selecting Gardenias For Zone 5 Gardens

Gardenias are beloved for their heady fragrance and waxy white blossoms that present a striking contrast to the deep green foliage. They are heat-loving evergreens, native to tropical Africa, and are best grown in USDA plant hardiness zones 10 and 11. Cold hardy gardenias are available in commerce, but that doesn’t guarantee zone 5 gardenia shrubs. Read on for more information if you are thinking of growing gardenias in zone 5.

Cold Hardy Gardenias

The term “cold hardy” when applied to gardenias does not mean zone 5 gardenia shrubs. It simply means shrubs that can tolerate cooler zones than the toasty areas in which they typically thrive. Some hardy gardenias grow in zone 8, and a few new ones survive in zone 7.

For example, the cultivar ‘Frost Proof’ offers cold hardy gardenias. However, the plants thrive only to

zone 7. Likewise, ‘Jubilation,” reputedly one of the hardiest gardenias, grows in zones 7 through 10. There simply are no gardenias for zone 5 backyards on the market. These plants have not been bred to survive severe cold.

This is not helpful to those planning on growing gardenias in zone 5 yards. In this low hardiness zone, winter temperatures regularly dip well below zero. Cold-fearing plants like gardenias simply won’t survive in your garden.

Growing Gardenias in Zone 5

You accept the fact that you won’t find cultivars for gardenias for zone 5. Yet, you are still interested in growing gardenias in zone 5. You have a few options.

If you want gardenias for zone 5, you’ll do best thinking container plants. You can grow gardenias as hothouse plants, you can raise them as houseplants or you can grow them as indoor plants taken outdoors in the summer.

It isn’t easy to help a gardenia to thrive indoors. If you want to try, remember that indoor zone 5 gardenia shrubs require bright light. Don’t mistakenly place the container in direct sun, which the plant will not tolerate. Keep the temperature about 60 degrees F. (15 C.), avoid cold drafts and keep the soil moist.

If you live in a particularly warm micro-climate in zone 5 regions, you might try planting one of the cold hardy gardenias in your garden and see what happens. But remember that even one hard freeze may kill a gardenia, so you will definitely need to protect your plant during winter.

Park Hill, OK– Crown Jewel® Gardenia PP19896 is a low-growing, spreading to prostrate gardenia with intensely fragrant, white, medium-sized double flowers beginning in early summer and repeating until frost. The heavy May flush of blooms is followed by repeat blooming throughout the summer, until fall brings another heavy flush of blooms. Light pruning after the first bloom-period will stimulate even more blossoms. Crown Jewel® Gardenia blooms on both old and new wood, so late frosts will not harm the crop of fragrant white flowers

Highly perfumed Crown Jewel® Gardenia is an easy care, broadleaf evergreen hybrid in a versatile dwarf size and requires little if any pruning to stay in shape. This garden jewel grows about 6 inches per year with the potential to reach 2 or 2 ½ feet in height and a spread of 4 to 6 feet wide, ideal for garden beds. The plant is hardy to zone 6 and bright green evergreen foliage is medium to small-sized for the species, with a soft texture overall.

Crown Jewel® Gardenia is the very best selection from a controlled cross between dwarf ‘Kleim’s Hardy’ (dwarf habit, heavy bloom set) and ‘Chuck Hayes’ (cold-hardiness, twice-blooming, double flowers) by Philip Dark of Oakmont Nursery in Chathem County, North Carolina. Dark is a member of the consortium of growers, breeders, retailers and marketers that make up Garden Debut®, and he reports that cold testing is ongoing in Zone 5. .

Crown Jewel® Gardenia prefers well drained, moist soil and full sun to partial shade (a bit of afternoon shade is great) and good air circulation. A cooler, woodsy environment protects from the harsh reflective heat of concrete or asphalt. Shelter from cold winter winds helps to prevent tip dieback at the colder edge of the plants’ range. Organic compost is excellent or light applications of commercial azalea fertilizer or diluted acid-forming fertilizers are good, although too much can burn tender roots.

Among its many landscape uses, Crown Jewel® Gardenia is perfect as a specimen adding color, fragrance, form and texture; a low accent plant in the garden; for winter interest; or as part of mass plantings. It is an excellent evergreen plant for containers where the fragrance can be enjoyed on decks and patios. While cold-climate gardeners must over-winter their gardenias indoors (can be grown as houseplant), in U.S.D.A. Climate Zones 6 and warmer, gardenias are grown outdoors, permeating the garden with fragrance. (Testing in Zone 5 is ongoing.)

This genus is native to the tropical and subtropical regions of Africa, southern Asia, Australasia and Oceania. Gardenias are easily grown in the southeastern U.S. because they demand high humidity and rich, acidic soils to thrive.

For more information on Crown Jewel® Gardenia PP19896 and other superior plant introductions from Garden Debut®, visit www.gardendebut.com.

Statistics Chart for Crown Jewel® Gardenia PP19896 Gardenia augusta ‘Crown Jewel’

Plant Category:

Spreading broadleaf evergreen shrub

Mature Height:

2 – 2 ½ feet in 10 years

Mature Spread:

3-5 feet, ideal for garden beds

Mature Form:

Low-growing, spreading to prostrate shrub


Twiggy growth hidden by shiny dark green leaves, tight brown bark

Growth Rate:

Naturally dwarf variety, 6 inches per year to 2 feet

Sun Exposure:

Partial or dappled sun (recommended), will tolerate either full sun or light shade

Soil Type:

Prefers rich, deep, well-drained, slightly acidic soils with a good moisture supply

Soil Moisture:

Best on moist, well-drained soils rich in organic matter. Follow a regular watering schedule during the first growing season while plants are getting established to promote a deep, extensive root system. Keep roots cool with a thick layer of organic mulch.


Fully double, medium-sized, waxy white flowers, measuring 2-3 inches in diameter begin in early June with heavy bloom, and flower throughout the summer until frost. Flowers perfume the landscape with a sweet fragrance.

Crown Jewel® is a cross between Kleim’s Hardy Gardenia (dwarf, heavy bloom set) and Chuck Hayes Gardenia (cold hardiness, double flowers, double bloom season)


Most outstanding characteristic of the Gardenia: the intense fragrance; flower scent is sweet, sweet, sweet! and surprisingly strong;

The natural fragrance of gardenia cannot be distillated and in perfumery, fragrances of orangeblossom, jasmine and tuberose are substituted for gardenia.


Broadleaf evergreen shrub with beautiful, shiny, deep green, oval leaves that contrast sharply with classic white gardenia flowers. Gardenia maintains beautiful, deep, rich green coloring all year long, foliage during winter

Landscape Uses:

Place near door, courtyard, patio, gate or entrance, in garden beds, along walkways or in containers on the deck, where handsome foliage and fragrant flowers may be enjoyed at close range.

Landscape uses include specimen, groundcover, border, container, woodland, cut flowers or indoor plant

Fragrant flowers with thick white petals are traditional for corsages or hair ornaments, for cutting, to float in a bowl of water on the dining table.

Bring into the greenhouse or home during winters in cold weather zones.

Floral Symbolism:

Gardenias symbolize purity and sweetness. They indicate secret love. They convey joy. They tell the receiver “you are lovely”

Root system :

Vigorous once established, with a moderate salinity tolerance

pH Level:

5 – 6.5, best on rich, deep, well-drained slightly acidic soils

Climate Zones:

6 – 11 (winter lows 0 degrees F. to above 40 degrees F.) (Zone 5 testing is ongoing)


U.S., Philip Dark of Oakmont Nursery, Chathem County, NC

When performance counts, use Garden Debut® introductions!

Gardenias can survive cold winter in southern New Jersey with a little care

I love gardenias. Whenever I pass the hardy gardenia plants in the nursery, I have to stop to smell them. They are truly one of my favorite scents. I have a beautiful bloom on my kitchen table right now.

I had these fragrant, romantic flowers in my August wedding bouquet almost 50 years ago. When I stop to sniff the gardenia plants in the nursery, I often pick a few to add to the wedding bouquets or arrangements that I am making for customers. Most people do not realize that these hardy gardenias can be planted outside year round and they will bloom all summer. There are hardy and there are tender gardenias. The hardy will grow outside all year long and the tender must be taken inside. You can plant some hardy ones now so they will establish prior to winter.

Some winters, I have tender gardenia in my sunny bay window. We take them inside and they bloom for a while, but as the days get long, cold and dark, they often do not bloom much until the longer days of spring begin after Valentine’s Day. They love sun and do not mind being cool at night. They especially want to have long drinks of water with plant food in it all summer and again in spring as the days get longer. I also have a spoon or so of time-release osmocote plant food in each pot or around plants outdoors each spring. This is a plant, like azalea, that will benefit when you dump your coffee grounds all around it.

In reading about gardenia, I found that they are related to the coffee plant. They are shiny evergreens and most grow in tropical places. There are a few, however, that will make it through the winter here in our USDA Zone 7 if they are planted in a somewhat protected site close to a wall and out of the wind. I have been reading a lot of online forums and discussion groups to see just how far north they have been grown outside and just what varieties do well. Many folks love their success with growing hardy gardenia outside all year long. With a somewhat protected site up along a house foundation, they seem to do well here in southern New Jersey.

Our son Joe has planted several outside. He seems to think that a good summer with adequate food and water, as well as a rich soil with a lot of humus in it and a site that is somewhat protected, will ensure success.

Sometimes a corner location with good morning sun that is protected by two walls helps these hardy perennials to survive a winter. Raking lots of leaves to almost cover the plant can also work wonders for winter protection. Last winter was cold for so long that some plants were damaged, but according to Joe, leave them in the ground and they often come back. He has some now sending up shoots. I just planted one along my walkway to the front door.

You, too, can plant a hardy gardenia, but try to do so soon so they can establish good roots long before winter. Since they like acidic soil, I will mulch each with chopped leaves in fall. That will also help moderate the soil for winter. Because we have sandy soil, I have to be sure to never allow the gardenia to dry out.

In summary, hardy gardenias should be planted in well-conditioned soil containing compost. Avoid cultivating around the plants, because that may damage their shallow roots. Mulch the plant with triple-shredded root mulch or chopped leaves to keep the soil moist, cool and weed-free. Feed the plants in spring with a time-release such as osmocote. Do not feed after July, as that might produce tender growth that will not be hardy in winter temperature. If the plant looks pale, yellowish-green, however, feed it now. I like a mild does of plant nutrient to restore plants to good health.

They seem to bloom best with moderate temperatures that drop down a bit in the evening. The ideal blooming temperature range is 65 to 85 degrees during the day and 60 to 65 degrees at night. Plants can be pruned as they finish a blooming cycle. If you want your plant to become bushier, pinch out the tips. Pinching will usually promote a heavier bloom the following year.

Although there are said to be several hardy gardenia, here are a few that have made it through the winter for us when planted in a protected area: Gardenia Frostprof, Gardenia Daisy, Gardenia Chuck Hayes and Gardenia Variegata. All can also be grown in a large urn or pot out on a deck and then kept in a bright, sunny garage or unheated porch or cool greenhouse over the winter. I like gardenia so much that I always try to have several in sunny windows. Email garden questions to [email protected]

Gardenias are a classic flower.

A cold hardy gardenia is a variety bred to withstand extremes of cold in comparison with most varieties of gardenia. This is an important distinction. By the standards of much of the continental United States, there is no such thing as a gardenia that is seriously hardy in cold weather.

Tropical Blooms

Gardenias are best adapted to tropical and subtropical conditions. Gardenias are native to Africa, Asia and the South Pacific. They haven’t yet been bred to endure severe winter cold. It is better to grow gardenias as hothouse plants, house plants or seasonal indoor/outdoor plants if your USDA climate is colder than USDA Zone 7. Beyond that zone it is possible to grow gardenias with limited success in micro-climates or in warm years, but hard frost will cause flower-drop and a hard freeze will kill a gardenia. The most consistently recommended climates are USDA Zones 9 and 10. Unless you are planting a specifically cold hardy gardenia you shouldn’t expect gardenias to grow well outside that range.

Basic Gardenia Facts

  • Gardenias are tropical and subtropical plants.
  • Gardenias grow best in a moist and humid climate but with limited direct water hitting the plant.
  • Even a cold hardy variety is unlikely to prosper as an outdoor plant beyond USDA Zone 7.
  • The colder your climate, the more carefully you should plan your planting and care of a gardenia if you intend to grow it outdoors.

Cold Hardy Gardenia Varieties

There are a small number of varieties that can be trusted to endure non-tropical conditions. Those few are commonly recognized and promoted. The Oregon Association of Nurseries recommends Kleim’s Hardy Gardenia and the Chuck Hayes or Oregon Gardenia. Other nurseries add the recently developed variety Frost Proof, but no varieties are recommended for climates colder than USDA zone seven.

Chuck Hayes

Chuck Hayes is a reliable variety with a classic, fully double blossom with a rich, traditional gardenia scent. Suited to container planting for those in cold climates it can grow to as much as four feet in height.

Kleim’s Hardy Gardenia

Kleim’s Hardy carries a single blossom similar to apple blossom in shape and form. The scent is again traditional gardenia, though not as intense as some. The shrub is low-growing to three feet, and well shaped for landscape use.

Frost Proof

Semi-doubled blossoms resemble narcissus when partially opened, with an outer star-like disc of petals and an inner cup. As the flower fully opens it becomes an informal, loose lightly doubled rosette. The bush is large, well suited to landscape and hedge use. The plant takes more sun than many gardenias, and is considered the most cold tolerant of the species to date.

Limits on Gardenias

Only these few varieties can withstand more cold than a tender variety. Those recommended for Zone 7 can survive limited exposure to temperatures as low as 0 degrees F. Beyond that limit, other things must be considered. Gardenias are subject to mold and mildew when water comes in contact with the leaves or petals. High humidity is an advantage, but rain and watering systems can damage plants. It’s not even wise to plant gardenias anywhere condensation can cause dew to drop down from neighboring plants. Soil should be moist, acidic, and well-drained, with plenty of organic matter added. Provide regular care and pruning for gardenias to ensure good air circulation within and around the plant.


Even chill resistant gardenias will do best when you take the time to prepare the planting site and develop good conditions for growth. The planting site should be in soil with a pH of 4.5 to 5.5. If your soil is not naturally this acidic you can prepare using organic material: peat moss, compost and pine mulch are all recommended ways of increasing soil pH. Soils with a high organic content also tend to drain better than clay soils, while retaining enough water to provide for the plant. Set your plants well apart to make sure there is good ventilation. You should also avoid planting directly against a fence or wall to ensure ventilation. Water from below, using a drip or underground system if possible, to keep leaves and petals dry. If you live in a zone with variable weather that pushes the limits of a cold hardy gardenia then you should pay particular attention to micro-climates of your garden. A sheltered, south-facing site with good sun and a dark wall behind to absorb heat can improve the chances of your gardenia surviving a cold snap.

Make good use of cold tolerant varieties, micro-climate, and the possibility of container planting. With these methods you can enjoy gardenias with their lush, elegant perfume as a special summer treat regardless of where you live.

Gardenias are native to Eastern Asia (China, Taiwan and Japan). They are attractive, low maintenance shrubs with large, creamy white flowers and glossy green leaves. The flowers have an exquisite perfume that pervades surrounding areas and creates a magical, romantic atmosphere in the garden. Gardenias flower at their best in the warmer months of the year, usually from November to May.


Gardenia augusta ‘Florida’

This is one of the best gardenias available. It produces masses of perfumed flowers on a hardy plant. ‘Florida’ grows to about 1m x 1m (3’x3′). Other varieties of G. augusta with larger flowers include:

‘Magnifica’, which grows to about 2m x 1.5m (6’x5′), and ‘Professor Pucci’, a medium grower to about 1.5m (5′) tall.

‘True Love’

This newly released gardenia is set to rival ‘Florida’ in popularity and performance. It has heavily perfumed, large flowers (100mm across), and grows about 1m (3′) tall and 60cm (2′) wide. It is said to be more resistant to pests and diseases than the other varieties.

Growing gardenias

Gardenias like a slightly acidic, cool, moist, well-drained soil. They need some shade, particularly from the full summer heat in a hot or tropical climate. In cooler areas they are quite happy in full sun. Yellow leaves (particularly in spring) can be treated with an application of Epsom salts (sulfate of magnesium), but the plant is probably more in need of an all purpose fertiliser and a dose of iron (iron chelates). Apply in spring, when the weather begins to warm and yellow leaves begin to show. Gardenias are warm climate plants, which are at their best in a mild, humid climate. They are seen to perfection in frost-free areas north of Sydney and Perth, but will grow in cooler areas in a warm protected position.


‘True Love’ is available in New South Wales and Queensland, but may be difficult to find in other states. It costs about $20-$25 for a 200mm (8″) pot.

Australia’s best gardenia

‘Florida’ is one of Don’s favourite gardenias, but there are many other varieties available and not all of them have been properly assessed. If you grow gardenias, whether they be old favourites or some of the newer varieties, write to Burke’s Backyard and let us know which one you think is best. Send your letter to:

Burke’s Backyard
PO Box 929
Willoughby NSW 2068

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