How to Plant and Grow Gardenia (2024)

Gardenias (Gardenia jasminoides) are known—and grown—for their creamy white blooms and intoxicating fragrance. The shrub bears long, glossy, emerald-green leaves and aromatic white or yellow single or double blooms that arrive in early summer and continue for several weeks.

The shrub, sometimes called cape jasmine, is a broadleaf evergreen native to the tropical and subtropical regions of Africa, Asia, Australia, and the Pacific Islands. In North America, gardenias are primarily grown in warm, humid climates, but gardeners in cooler climates who crave the beloved blooms often attempt to grow them as houseplants. It can be done, but gardenias can be finicky and labor-intensive to cultivate regardless of whether they are grown inside or outside.

It should also be noted that gardenias are considered toxic to dogs, cats, and horses. The flowers, foliage, and berries are also considered mildly toxic to humans.

Where to Plant Gardenia

The quality of your soil is key to success when growing gardenias. To thrive, gardenias need well-drained, rich, acidic soil with a pH between 5.0 and 6.5. In areas where the soil pH is higher, it may be necessary to amend the soil or opt for container planting. Gardenias also prefer full sun but benefit from having a respite in the afternoon shade—especially in very hot climates. Plant them near patios or in east-facing garden spots where they will avoid getting scorched.

Gardenias are a classic addition to cutting gardens and—thanks to their heady fragrance—are perfect for planting near walkways or gathering spots where their scent can be enjoyed. To draw in nighttime pollinators, gardenias are known to expend even more fragrance when the sun goes down. This may be overbearing for those sensitive to smells if your gardenias are planted near screened windows. You can, however, take advantage of this habit by planting them in a moon garden near other night-blooming favorites like flowering tobacco, moonflowers, and four o’clocks. Just make sure to select shallow-rooted plants that won’t compete with the gardenia’s anti-social root zone or plant them with a wide enough berth to avoid overcrowding.

How and When to Plant Gardenia

If you are planting your gardenia outdoors, the best time to do so is in the fall or approximately six weeks before the first frost. In cooler climates, it may be best to wait for spring to avoid frost damage. Dig a hole twice as wide and slightly deeper than the plant’s root ball and place your gardenia in the hole, filling in the dirt until the root ball is even with the surface of the soil. Water thoroughly and add a 2-inch layer of mulch or pine straw around the plant leaving about 2 to 3 inches of bare soil at the base of the plant.

If you are attempting to grow gardenia indoors, you can plant it any time of the year, just be sure to keep your plant away from air conditioning and heat vents. Keep your potted gardenia in an area that remains approximately 60 to 70ᵒF and gets at least 6 to 8 hours of bright, indirect sunlight. Once it is potted, you can increase the ambient humidity for your gardenia by placing it on a shallow tray filled with pebbles and water or by placing a humidifier nearby.

Gardenia Care Tips

One of the most common reasons gardenias fail in a garden is because they need acidic soil. However, when grown properly, their foliage creates a wonderful backdrop for other plants and the signature gardenia bloom scent is worth any extra effort it takes to cultivate them.

Light

Gardenias prefer full sun with spots of shade to protect their delicate leaves and flowers from scorching when summer heat is at its peak. In the hottest zones, it’s best to find a planting spot with ample morning sun and afternoon shade.

If you are planning to grow gardenias indoors, they need as much sunlight as possible. This encourages a good bloom set as well as deep green foliage.

Soil and Water

Gardenias require humus-rich, acidic, well-draining soil. Before planting them in the ground, test your soil pH levels to ensure they are between 5.0 and 6.0. If your soil leans more alkaline, you will need to amend the soil or consider a different location.

Despite their fussiness over well-draining soil, gardenias are not drought tolerant. So, it is important to keep the soil around your gardenia consistently moist (but not wet). Plan to give your plants at least an inch of water per week (or more during dry spells) and don’t let the soil dry out between waterings. Adding a layer of mulch may help retain soil moisture and prevent weeds from creeping in and competing for nutrients.

Temperature and Humidity

Gardenias are native to tropical and subtropical climates, so they prefer temperatures between 60-70 degrees Fahrenheit during the day and 60-65 degrees Fahrenheit at night.

Gardenias also prefer their ambient humidity levels consistently above 60%. This makes growing gardenias as a houseplant challenging. If you plan to grow yours indoors, you may need to use a humidifier or mister near your gardenia plant to keep the air moist.

Fertilizer

If you are growing your gardenias in the ground, plan to fertilize them in early spring and again in early summer with an acid-rich fertilizer that can be easily absorbed by the plant’s roots. A good bet is to look for a fertilizer designed for other acid-loving plants like camellias, rhododendrons, or blueberries. Err on the side of under-feeding and stop fertilization in the fall to allow the plant to slow growth before entering dormancy.

Container-grown gardenias may need to be fed every few weeks during the active growing season but should also avoid getting fertilizer in the fall and winter. It's best to use acidic-based fertilizers and also keep in mind that water affects the soil's acidity.

Pruning

Gardenias don’t need much pruning, but you can cut them back a little every two years to maintain their shape. Wait until the blooming season ends and then use sharp, sterile shears to cut back some of the foliage as well as the green and woody growth. You can cut the plant back by as much as two-thirds.

Potting and Repotting

When growing gardenias in containers, choose a container with excellent drainage that is at least 4 to 6 inches larger than your plant’s nursery pot. Sprinkle a layer of soil designed for acid-loving plants in the bottom of your container, add your gardenia, and fill in the pot with soil, but don't tamp it down. Overly compacted soil may limit drainage and lead to root rot. Once it is planted, water your gardenia thoroughly. Place your potted gardenia in an area that receives 6 to 8 hours of sunlight, but has protection from harsh afternoon rays. Keep the soil consistently moist but be mindful of overwatering. Your newly planted gardenia will need more water to help establish the roots, but after that, you’ll only need to water it when the first few inches of soil feel dry.

Your container-grown gardenia will not need extra feeding and watering over the winter, but if you live in a climate with colder winters, you may want to protect your plant by moving it into a cool garage for the season. While it is inside, keep the soil moist, but not wet.

Your container-grown gardenias may need to be repotted every 2 to 3 years, but it’s best to wait until the task is absolutely necessary. Gardenias don’t take well to transplantation and are susceptible to transplant shock and a heightened risk of root rot when disturbed. If you need to transplant your gardenia, wait until the blooming season ends and then hydrate your plant well approximately 12 to 24 hours before moving.

To repot, grasp the base of the plant and remove it from its container. Without disturbing the root system too much, inspect the roots for pests and issues and deal with them if need be. Once your plant is ready, place a small amount of slightly acidic potting mix in the bottom of your new pot and place the plant in the center of the pot before filling it in with the rest of the new soil. Do not pat the soil down, but make sure the top of the plant’s root ball is even with the soil line. Water your newly transported gardenia well and return it to its sunny location.

Pests and Problems

Gardenias can be susceptible to a wide variety of pests and diseases. Two common pests are mealybugs and scale, which are often found feeding on the stems and undersides of the leaves. Mealybugs are identified by their cottony white egg sacks, while scale is a hard, brown-shelled pest that does not move. Whiteflies, which have small green bodies with white wings, are also found on the undersides of leaves. Sooty mold on the foliage may be an indicator of an infestation of the flies and the sticky honeydew they secrete. All of these pests are fairly easy to control with insecticidal soaps, though scale can be tricky because of their hard outer shells. To manage these common pests, use a systemic insecticide.

Gardenias can also be plagued by powdery mildew, anthracnose, leaf spot, and dieback. Make sure your gardenias have ample airflow, well-drained soil, and are not overwatered to prevent many of these issues.

Bud drop is another common problem for gardenias. This is usually caused by issues with humidity, overwatering, or insufficient light.

How to Propagate Gardenia

The easiest way to propagate gardenias yourself is via softwood cuttings. You can do so by taking a 4 to 6-inch green section (just below a leaf or node) from the tip of a branch in early spring when new growth starts. Remove all but the topmost leaves. Dip the cut end in rooting hormone and stick it into a grow pot filled with equal parts perlite and potting soil. Place the entire grow pot in a plastic bag, but add a stake or chopstick to the soil to keep the bag from touching the cutting. Place your cutting in a warm place that receives about 6 to 8 hours of bright, indirect sunlight, and keep the soil consistently moist. After it has rooted (4 to 8 weeks), you can transplant your cutting to a larger pot or your garden.

Propagating gardenias via seed can be done, but it is a more complicated process that requires a few years before you will be rewarded with flowers. To do so, collect gardenia seeds from spent seed pods and allow them to dry for several weeks. When you are ready, plant your seeds on the surface of a grow pot filled with a mix of perlite and peat moss. Sprinkle potting mix on top of the seeds and place the pot in a warm area out of direct sunlight until the seeds begin to germinate. Keep the soil moist until you see sprouts develop. This will likely take about 4 to 6 weeks. When your seedlings are about 4 to 6 inches tall, transplant them to slightly larger pots filled with peat-based potting soil and place them in an area that receives 6 to 8 hours of bright, indirect sunlight. You can transplant your seedlings to your garden or a larger pot when each seedling has several sets of leaves.

Types of Gardenia

Everblooming Gardenia

Gardenia augusta 'Veitchii' bears white double flowers over a longer season on a 6-foot-tall shrub. It is hardy in zones 8-10.

'Mystery' Gardenia

'Mystery' bears pure-white semidouble flowers on a compact shrub that grows to 3 feet tall and 5 feet wide in zones 8-10.

'Kleim's Hardy' Gardenia

Gardenia jasminoides 'Kleim's Hardy' is a cultivar that is hardy in zones 7-11. Its compact size (just 2 to 3 feet in height) makes it ideal for containers or for planting along walkways. In the spring and summer, it bears richly fragrant white blooms with bright yellow stamens atop emerald-green foliage.

'Radicans' Gardenia

Gardenia jasminoides 'Radicans' is a creeping gardenia native to southern China, Taiwan, Japan, and Vietnam. It is hardy in zones 7-8 and has a low, mounding habit with shiny, evergreen foliage and fragrant white or cream flowers that appear in spring and summer. It is considered a true miniature gardenia with blooms measuring approximately 1 to 2 inches wide.

'Frostproof' Gardenia

Noted for its cold hardiness, Gardenia jasminoides ‘Frostproof’ is an evergreen shrub that typically grows to 4 or 5 feet tall in zones 7-11. It bears sweetly fragrant, white double blooms in early summer and can withstand the spring frosts of cooler climates (including short periods of temperatures as low as 0-10°F) without damage.

Companion Plants for Gardenia

Camellia

Camellias are perennial shrubs that produce pretty (sometimes fragrant) blooms in spring, fall, or even winter in milder climates. They are slow growing, only gaining about 12 inches per year once established, but can grow as tall as 20 feet in the right conditions. Camellia shrubs have similar soil, sun, and water requirements as gardenias, but will not compete for nutrients when planted at least 5 feet apart.

Signet Marigold

Signet marigolds—not to be confused with African or French marigolds—are mounding annuals that typically grow to just 6 to 12 inches in height. Signet marigolds are hardy in zones 2-11 and tend to bloom from May or June until the first frost in most climates. Like gardenias, signet marigolds enjoy lots of sun and moist, well-drained soil. They also make a great companion for gardenias because they tend to attract butterflies while repelling blackflies, whiteflies, and aphids.

Sweet Marjoram

Sweet marjoram (Origanum majorana) grows best in hardiness zones 9-10 and loves full sun and loamy, well-draining soil. It is a popular addition to pollinator and edible gardens and a common companion plant for gardenias because the strong scent of sweet marjoram tends to mask the sweet smell of the gardenia blooms. This helps repel destructive pests (like aphids), but will not prevent you from enjoying the sweet gardenia scent.

Salvia

There are nearly 1,000 species of salvia that grow in hardiness zones 3-10 including annual, biennial, and perennial varieties. Like gardenias, perennial salvias prefer well-drained, slightly acidic soil with a pH of 5.5 to 6.5. Unlike gardenias, however, salvias can tolerate long periods of drought and will thrive in full, hot sun. This makes them a great plant to place in areas with less protection from the high afternoon sun.