How to Grow Gorgeous GardeniasWhether you grow them outdoors in the garden or indoors as houseplants, gardenias can thrive just about anywhere if you are willing to indulge them
In the languid warmth of late spring and early summer, many gardens in the South are filled with the heady perfume of gardenias in bloom. But even if you don’t live in a sultry southern climate, you can still enjoy the creamy white flowers and intoxicating fragrance of these striking evergreen shrubs by giving them the subtropical conditions they love.
Gardenias are known for their romantic white flowers and glossy green leaves. Photo by: Del Boy / Shutterstock.
Gardenia or Cape Jasmine
The most popular cultivated species is Gardenia jasminoides (also called G. augusta or G. grandiflora).
8-11; hardier frost-resistant cultivars can be grown in zone 7 and will tolerate below-freezing temperatures. In zones where gardenias are not winter hardy, use them as lush summer container plants on patios and front porches or as temporary transplants in the garden, moving them to a sheltered location when fall approaches. Or try growing dwarf varieties of gardenias in pots on a balcony or indoors in a sunlit room.
Typically May through June, with some varieties blooming into autumn.
Gardenias are available in shrub, tree and dwarf forms, many of which are suitable for potting. They typically grow to a height of 3 to 8 feet with an equal spread, depending on the cultivar. Dwarf varieties range in height from 6 inches to 2 feet.
Color is typically white, with single, semi-double, or double blossoms ranging from 2 to 5 inches in diameter. Some cultivars, such as ‘Golden Magic’, have buttery yellow blossoms.
Glossy, dark green leaves, 2 to 4 inches long. Even when gardenias are not in bloom, the glossy emerald-green foliage, which is almost as lovely as the flowers, will remain attractive throughout the year.
Gardenias bloom best when planted in well-drained, acidic soil. Photo by: Paul Brennan | Dreamstime.
Plant gardenias in light shade, preferably where they will be protected from harsh afternoon sunlight. Gardenias need good air circulation, so don’t crowd them closely together. In regions where they are marginally hardy, plant gardenias in a location protected from hard freezes and drying winter winds. As with many spring-blooming shrubs, fall is the best time for planting because it gives the root system more time to get established.
Gardenias demand a well-drained, acidic soil (with a pH of less than 6.0) that is rich in organic matter. Add peat moss or compost when planting, then apply a few inches of mulch around your plants to keep them moist (but be sure to keep it away from the crown of the plant). Gardenias have shallow root systems, so avoid cultivating around the root zone once they are established.
Gardenias like consistently moist but not soggy soil, and require about an inch of rain (or equivalent watering) per week. In containers, use a light, well-drained soil and keep plants evenly watered.
Fertilize gardenias lightly in spring, once the chance for frost has passed, with a slow-release fertilizer for acid-loving plants, such as an azalea fertilizer. Look for a formulation that includes iron and magnesium. Then fertilize your plants once again in late June. Another option is to use a half dose of fertilizer more frequently. Make sure the soil is moist before and after fertilizing. If you plan to overwinter your gardenias outdoors, do not fertilize them in the fall, new growth may be killed if temperatures drop below 15 degrees F.
Prune gardenia shrubs in summer after they have finished flowering so you don’t remove any buds. Before pruning, make sure the variety you’re growing only blooms once and has completed its blooming cycle. If it does bloom more than once, prune off faded flowers just below the leaf node to encourage repeat blooming.
Pests and other problems:
Gardenias are susceptible to several pests and diseases, including whiteflies, mealybugs, and powdery mildew. For guidance on controlling and troubleshooting these problems, see Gardenia Insects & Related Pests and Gardenia Diseases and Other Problems from the Clemson University Cooperative Extension Service.
Gardenias are popular houseplants for their attractive flowers, foliage and sweet scent. Photo by: Steffen Hauser / botanikfoto / Alamy Stock Photo.
“A gardenia is not the easiest plant to bring into bloom [indoors], though plants that are happy with their situation will often bloom in late spring and again in the fall. In between, they enjoy spending the summer outdoors in a shady spot,” says Barbara Pleasant, author of The Complete Houseplant Survival Manual.
Several varieties of gardenias grow to only 24 inches, and you’ll often find them sold in pots at garden centers for indoor use. But unless you have a greenhouse or sunroom, it will be difficult to give indoor plants enough sunlight and humidity to produce flower buds. Pleasant recommends placing your plants in a south-facing window where they will receive at least four hours of sunlight daily, but not strong midday sun. To increase humidity, place a humidifier in the room or place your pots in a tray of damp pebbles. Cool nighttime temperatures (60 degrees F) and warm daytime temperatures (75 degrees F) will promote better flowering. Gardenias can be toxic to cats and dogs if ingested, so be sure to place them in an inaccessible location if you have pets.
Use a well-drained, acidic soil, such as a mix of 2 parts potting soil and 1 part peat moss.
Keep soil evenly moist at all times, but do not overwater or allow puddling.
Feed every two weeks with a balanced houseplant fertilizer that contains micronutrients, especially iron, or use a slow-release azalea fertilizer. A lack of iron or a soil that’s too alkaline can lead to yellowing leaves.
Repotting and propagation:
Repot young plants annually in late winter until the roots fill 8-inch pots, then repot every two years to refresh the soil. To propagate, take 3-inch stem cuttings in spring or early summer and dip the cut ends in rooting powder to speed root development. High humidity is essential to success, says Pleasant, so place the cuttings in a moist potting mix and enclose in a plastic bag, container and all, for the first two weeks.
If you struggle to grow gardenias, try Mitriostigma axillare, the African gardenia, with sweetly-scented flowers that bloom all year. Many gardeners find it very easy to care for.
Landscape Design Tips
Use gardenias as hedge plants along sidewalks, entryways, and fences or as specimen plants anywhere in the garden where their fragrance can be appreciated. Low-growing spreading cultivars, such as ‘Radicans’, are attractive in borders or as groundcovers.
Potted gardenias are perfect for porches and patios, where you can shelter them from harsh sunlight and winds and easily move them indoors if desired (see our guide to bringing outdoor plants inside). Tree forms are especially lovely when grown in containers, and add sophistication to formal garden designs.
Create a cocktail-hour garden by combining gardenias with other white-flowering plants that will reflect the moonlight and perfume the night air (see Creating Night Garden Drama). Gardenias are most fragrant at sunset and during the early evening hours. The moonlit white flowers will also attract nocturnal moths, which serve as pollinators.
Indoors, you can control the size of gardenias by growing them in smaller containers. In fact, a slightly pot-bound gardenia will often bloom more prolifically. Gardenias also make excellent bonsai trees if you prune and train them into the desired shape (see these tips from Dallas Bonsai).
Varieties to Try
'White Gem' is the crown jewel of dwarf gardenias for growing indoors because it only reaches a height of 1 to 2 feet. It’s adorned with daisylike white flowers with yellow centers in late spring and early summer.
'Veitchii' is a reliable everblooming gardenia that yields pure white, rose-like flowers from spring into fall and will continue blooming throughout the year when kept in a warm environment, such as a greenhouse or sunroom. Grows up to 4 feet tall and 3 feet wide.
'Frostproof' is hardier than other varieties and flowers heavily in late spring. It’s upright habit makes it an ideal plant for a hedge or along foundations. Can take more sun than other gardenias.
'Kleim’s Hardy' is also grown for its cold resistance (to zone 7). It has a mounding habit, with 2 inch, fragrant flowers and is a popular choice for containers. In colder areas it blooms from midspring to early summer, while in warmer areas, it may bloom all year.
'Radicans', another dwarf variety, grows only 6 to12 inches tall but spreads up to 3 feet wide, making it ideal for use as a fragrant groundcover or for shaping into a bonsai tree. From late spring through early summer, it is covered with dainty 1-inch white flowers, set off by lustrous dark-green leaves.
'Mystery''Mystery', in addition to its alluring name, is noted for its enormous donut-sized double flowers, which span up to 5 inches across. This attractive rounded shrub grows 6 to 8 feet tall with an equal spread and blooms from midspring through early summer, with sporadic flowering into fall.
'August Beauty' is prized for its long bloom time, producing an abundance of double white flowers up to 3 inches across from May through September. Growing 4 to 6 feet high and 3 to 4 feet wide, it has a shrubby habit well suited for hedges.
The foliage of 'Variegata' is every bit as attractive as the highly fragrant flowers, displaying cream-colored markings that add year-round interest. Suitable for containers or small hedges, this compact cultivar grows 3 to 4 feet tall and wide.
'Golden Magic' produces luscious double yellow flowers continuously during warm weather. Its rounded, compact habit (2 to 3 feet tall and wide) makes it a favorite for containers and by entryways.
‘Chuck Hayes’ is an extra-hardy cultivar that tolerates both heat and cold (down to Zone 7). It produces velvety white 3-inch flowers in profusion from late spring through early summer, and will often rebloom in fall. Grows up to 4 feet tall and wide.
ScentAmazing is another cold-hardy reblooming gardenia with, as the name implies, an out-of-this-world fragrance. Grow this compact 3-foot shrub in containers on patios and near entryways, or wherever its irresistible scent will be most welcome.
Other fragrant plants to grow: