How to Plant, Grow and Care For Gardenias

Are you looking to add some gardenias to your outdoor or indoor garden, but aren't quite sure where to start? These popular plants are well known for their fragrant scent and beautiful blooms. In this article, gardening expert Melissa Strauss shares all you need to know about growing gardenias in your garden, including their maintenance and care needs.

Gardenia

Contents

Gardenias are known far and wide for their intoxicating scent as well as their beautiful white flowers. They are a fairly common garden flower due to their low-maintenance nature and adaptability. They can grow quite well both indoors and outdoors. Gardenias are close relatives to the coffee plant, which shares similar, glossy, green foliage and aromatic blossoms.

The creamy white flowers with their dreamy redolence are a prized perennial shrub in many a classic Southern Garden. After the last great freeze in my area, they were one of the very few beloved plants left unscathed in my personal garden, and so, suffice it to say, I am a Gardenia believer.

There are more than 200 varieties of gardenia, each one lovelier than the last. If you’ve decided to add this hardy shrub to your garden this season, you’ve made an excellent choice. Continue on to find out all you need to about successfully growing gardenias both indoors and outdoors this season.

Gardenia Overview

Gardenia Overview
Scientific Name Gardenia
Plant Type Perennial Evergreen Shrubs
Season Spring, Summer, and Fall
Pests Whiteflies, Japanese Wax Scales
Family Rubiaceae
Exposure Full Sun to Part Sun
Diseases Root Rot, Stem Canker, Bud Drop
Genus Gardenia
Plant Spacing 3’-8’
Varieties more than 200
Maintenance Moderate
Planting Depth 12” wide and deep
Soil Type Acidic, Loamy, Well Drained, Moist
Native Area Asia
Height 3’-8’ tall and wide
Plant with Hydrangeas, Rhododendrons
Hardiness Zone 7-11
Watering Needs Moderate

Classification

Gardenias are perennial evergreen shrubs. They hold their glossy foliage year-round. They are quite cold-tolerant and will bloom year after year if properly cared for.

Their evergreen nature makes them an attractive shrub all year. Gardenias are mainly classified by size and flower formation. The two most popular species are G. jasminoides and G. taitensis.

G. jasminoides

Close-up of a gardenia flower against a blurred background of dark green glossy leaves. The flower is large, rose-shaped, white, with double petals and slightly wavy edges. The petals are tightly clustered, covering the center of the flower.
Gardenia jasmoinoides is a large shrub with fragrant white flowers and glossy dark green leaves.

Gardenia jasmoinoides is the most common species of gardenia. Also known as Cape Jasmine, it is a large shrub with highly fragrant flowers which can bloom year-round in warmer climates, and in spring and summer in cooler climates.

This winner of the Royal Horticultural Society’s Award of Garden Merit is a versatile plant. It can grow in full sun to light shade, make a wonderful privacy hedge, and their double-petaled blooms make wonderful cut flowers.

G. taitensis

Close-up of a flowering shrub Gardenia taitensis in a sunny garden. The plant has lush, dark green, glossy foliage, oval in shape. The flower is small, pinwheel-shaped, white, with a slight yellow glow in the center.
Gardenia taitensis is a tropical evergreen shrub with small, pinwheel-shaped white flowers.

The Tahitian gardenia, or tiare flower, is a large, tropical, evergreen shrub. It is native to the South Pacific despite being named otherwise. It is from the small, pinwheel-shaped flowers of the Tahitian Gardenia that monoi oil is derived.

These pretty blooms are also, commonly made into flower necklaces called “Ei” in the Cook Islands, and “Lei” in Hawaii.

Leaf Formation

Close-up of a flowering gardenia plant in a garden. The plant has beautiful, dark green, glossy oval-shaped leaves, and a beautiful double white rose-shaped flower.
Gardenias have a whorl of glossy ovate dark green leaves.

The leaf formations of most gardenia plants are a whorl of shiny, dark green, ovate leaves. The color and size can vary by species and variety.

Gardenias are always evergreen and retain their pretty foliage even in quite cold temperatures. Even in a hard freeze, it is common for gardenias to retain their foliage unscathed.

Flowers

Close-up of a Gardenia flower against a background of blurred dark green foliage. The flower is large, double, has beautiful rounded white waxy petals, reminiscent of a rose flower.
Gardenias produce delightful, fragrant white waxy flowers.

Gardenias are best known for their wonderfully fragrant flowers. Their blooms are white, although, in soil that is too alkaline, there is a chance they may turn yellow.

All Gardenias have fragrant flowers. Their creamy, waxy, white blooms come in single and double-petal forms and rose forms. They range in size from only a few centimeters wide, to 5”-6” inches in diameter.

Propagation

Gardenias are not difficult to propagate, however, like most plants, when grown from seed, it takes several years for them to flower. Gardenias propagated from cuttings will flower much sooner, so this is generally the preferred method.

From Cuttings

Close-up of a woman's hand holding a cutting of a gardenia with fine white roots, over a flower pot filled with moist soil. The cutting has bright green stems, at the top of which grow two oval, glossy green leaves.
The cutting must be dipped in the rooting hormone and placed in moist soil.

Propagating Gardenias from cuttings is a simple process and one that can work in tandem with pruning. A cutting should be at least 5” long and should include the tip of the branch. This works best if the cuttings are taken from green wood (new growth) as these will root quickly.

Prepare a pot with moist peat or potting soil. Dip the cut end of the gardenia in rooting hormone, and then simply stick your finger in the soil to make a hole and place the end of the cutting in the hole.

Set your potted cutting in bright, but indirect light, keeping the soil moist. Your cutting will take about 4-6 weeks to develop roots. Try to keep your cutting in a humid space during the rooting process, this will ensure that the foliage remains healthy until the roots are stable enough to support it.

From Seeds

Close-up of Gardenia fruits in a black bowl on a wooden table. Women's hands hold several fruits over the table. The fruits are oval, dark orange, slightly wrinkled, with green tails on the tops. These fruits contain seeds.
Be sure to soak the seeds before sowing and sow them in well-drained soil about ¼ inch deep.

Gardenias propagated by seed are a little bit unpredictable. The germination time of gardenia seeds can vary widely, from a few weeks to a few months. Germinating seeds is typically the most successful when fresh seeds are sown. Seeds should be soaked overnight, before sowing.

Seeds should be sown about ¼ of an inch deep. Soil that drains well but holds some moisture should be used, perlite or a mixture of peat moss and sand both work well. Try to keep the soil moist and keep the temperature steady at around 75°F.

Grafting

A close-up of a branch of a plant that propagates by grafting, against a blurred background of a sunny garden. A bag of wet soil is attached to a branch of a plant with white plastic ties.
Grafting allows you to get plants more resistant to pests.

Gardenias can also be propagated by grafting. This is typically done to produce plants with higher pest resistance and involves grafting the desired variety onto rootstock that comes from a resistant cultivar.

How to Grow Gardenias

Gardenias fall into the category of being moderate in maintenance. While they have some specific needs, and will not thrive in opposing conditions, if they are planted properly, they are drought and cold-resistant, and most will bloom with or without fertilizer.

However, there are ways to maximize your gardenia’s flowering potential, which is what we all look forward to when planting one of these lovely shrubs.

Planting Depth and Potting

Close-up of female hands in green gloves transplanting gardenias into a white pot, among evergreen potted plants on a white table. The gardenia plant has beautiful whorls of glossy green, oval leaves. There is also a white watering can and a potted plant with variegated leaves on the table.
When growing gardenias in containers, make sure there is enough room to grow and it has a drainage hole.

Gardenias don’t make very good houseplants, however, they do quite well as outdoor container plants. Choose a container that gives your gardenia room to grow, as they don’t love being transplanted. Your container should also have a drainage hole, as gardenias do not tolerate soggy roots.

If you live north of zone 7, planting your gardenia in a pot is a must, as it will need to come in when temperatures drop below freezing for long periods. South of zone 7, your gardenias should be perfectly fine in the ground all year. I live in zone 8 and my gardenias never suffer in the winter.

When planting gardenias in the ground, dig a hole that is twice the width, but only as deep as the root ball. Make sure you are choosing a spot with proper drainage.

Gardenias also thrive in soil that is slightly acidic (5.0-6.5). Adding organic material to sandy soil will help raise the acidity and make these shrubs happier.

Light

Close-up of a flowering Gardenia plant in full sun in a garden. The plant has lush whorls of shiny, dark green, oval leaves and medium-sized, double, white, rose-shaped flowers.
Gardenias grow well in bright, indirect sunlight.

Gardenias are versatile when it comes to light needs. Ideally, they do best with several hours of sun, early in the day. In cooler climates, your gardenia will appreciate full sun, but in warm climates, gardenias need some shelter from the mid-day/afternoon sun.

Too little sun will cause gardenias to take on a leggy growth habit, and a scarcity of flowers. Giving a gardenia plenty of sun will cause it to produce more flowers for a longer time period. But be careful. Too much sun will shorten the life of those blooms.

Water

Gardenia flowers bloom in the garden surrounded by beautiful, dark green leaves. The flowers are large, white, not fully blossomed, double, have oval petals covered with drops of water. The leaves are oval, shiny, evergreen.
Gardenias prefer moderate watering, about 2-4 inches of water per week to thrive.

Gardenias have moderate watering needs. Once they are established, they are more drought tolerant, but they don’t do well in completely dry soil. Gardenias need about 2-4 inches of water weekly to perform their best.

This water can come from rain or the hose. Mulching around the base of the plant will help hold in moisture and keep your gardenia healthier in general.

Climate and Temperature

Close-up of a beautiful blooming evergreen gardenia shrub in a sunny garden. The plant has beautiful oval, slightly elongated, dark green leaves and single, open, pinwheel-shaped white flowers with a yellow glow in the centers.
Gardenias need high humidity and plenty of sunlight.

Gardenias thrive in tropical weather. They like humidity and plenty of sun. If you are growing a gardenia south of zone 8, make sure that it gets some respite from the sun during the hotter hours.

Gardenias won’t bloom without a daytime temperature that consistently stays at or above 70°F and around 10° colder at night. They like a humidity level that stays above 60% most of the time.

Most gardenias are cold tolerant to 10°F for a short period. They can survive a hard freeze, but not for a long duration. Gardenias will hold onto their leaves but will not bloom in colder weather. In warm climates, however, it is not impossible for a gardenia to bloom year-round.

Fertilizing

Close-up of a man's hand with granular fertilizer, on a blurred background. Fertilizers are small round granules of blue color. The gardener is dressed in a plaid shirt with long sleeves.
Gardenia prefers regular fertilizing in spring and summer intended for acid-loving plants.

Gardenias benefit from regular fertilizing in spring and summer, but during the fall and winter, fertilizing should be avoided. In spring, give gardenias a fertilizer formulated for acid-loving plants, such as camellias or azaleas.

In addition to nitrogen, phosphorous, and potassium, gardenias also need copper and iron. Keep a lookout for these items in your fertilizer.

As an alternative to commercial fertilizers, gardenias will benefit from a periodic application of coffee grounds and Epsom salt solution. Don’t fertilize more than once per month, as too much fertilizer can be as harmful as none at all. A gardenia that is over-fertilized will wilt and drop flowers early.

Pruning and Maintenance

Close-up of a large Gardenia bush in the garden. The plant has lush branches covered with whorls of dark green, shiny, ovoid leaves, and lush, double, white buds. The flowers are large, have rounded petals arranged in several layers, resembling rosebuds. Some buds have wilted and become dry, shriveled, dark brown, and need pruning.
Gardenias require deadheading and pruning the ends of all branches to form new green shoots.

Gardenias benefit greatly from pruning. Deadheading should be a regular practice with gardenias in bloom. Plucking off spent flowers will encourage the plant to set more buds, as well as save and redirect energy toward new growth. Avoid hard pruning and avoid pruning too late in the year.

Pruning should take place in the summer when the plant is finished blooming. This is typically around July. Trim 2”-3” from the ends of all the branches and avoid cutting back by more than 1/3 at the most.

New green shoots will grow from the cut branches, and they need to strengthen a bit before wintertime. Pruning too late in the year can result in frost damage to the newer growth.

Toxicity

Close-up of a flowering gardenia bush in the garden. The bush is covered with thick, ovate, glossy green leaves. The large white flower has double petals and resembles a rose.
This plant is toxic to pets and can cause diarrhea and an allergic reaction.

Gardenia plants are toxic to cats, dogs, and horses. If kept indoors, they should be kept out of the reach of children and pets. Ingestion of a gardenia plant causes vomiting and diarrhea, as well as an allergic reaction in some cases.

There are a few different popular varieties of gardenias. Let’s take a look at some of the most common varieties you’ll see, as well as where they will survive best, whether that’ s indoors or outdoors.

‘Aimee’

Close-up of a G. jasminoides 'Aimee' flower against a blurred background of leaves. The flower is large, white, double, has rounded, slightly wavy-edged petals arranged in several layers, resembling roses in shape.
‘Aimee’ has large and fragrant white rose-shaped flowers.
botanical-name botanical name G. jasminoides ‘Aimee’
sun-requirements sun requirements Full to Part Sun
hardiness-zones hardiness zones 8-11

This vareity is known for its extra-large, extra-fragrant blossoms. These rose-form flowers are 4”-5” wide and the perfect shade of cream which compliments its deep green, glossy foliage. This variety blooms from spring through summer.

You will definitely want to plant this shrub in a spot that sees plenty of traffic. The scent is glorious, and the plant is generous with its fragrance.

‘Buttons’

Close-up of a G. jasminoides 'Buttons' flower against a blurred leafy background. The flower is large, open, has double white petals and an unusual center resembling a button.
‘Buttons’ grows well in lightly shaded areas, producing double white flowers with button-like centers when fully open.
botanical-name botanical name G. jasminoides ‘Buttons’
sun-requirements sun requirements Full to Part Sun
hardiness-zones hardiness zones 8-11

This is a small variety of G. jasminoides with a mounding habit. This shrub prefers to be planted in a slightly shaded spot. Its deep green, glossy leaves are small and ovate and pointed at the ends.

Buttons has small flowers (2” in diameter) that have double petal form and open fully to reveal pretty yellow centers which resemble buttons.

‘Frostproof’

Close-up of a G. jasminoides 'Frostproof' flower against a blurred background of dark green foliage. The flower is large, white, terry, has oval petals with slightly wavy edges.
This cold-tolerant gardenia produces delicate double-petalled flowers, about 3 cm in diameter.
botanical-name botanical name G. jasminoides ‘Frostproof’
sun-requirements sun requirements Full to Part Sun
hardiness-zones hardiness zones 7-11

The name says it all for this cold-tolerant gardenia. I have two of these lovely plants in my yard, and they are every bit as cold-tolerant as my camellias. This is shocking because their leaves are really quite delicate.

‘Frostproof’ is also very heat tolerant, making it an all-around hardy and easily managed variety. The blooms are double-petaled and about 3” in diameter. Frostproof is a slow grower but ultimately reaches up to 5’ tall and 4’ wide.

‘Radicans’

Close-up of G. jasminoides 'Radicans' flowers surrounded by dark green foliage. The leaves are dark green, glossy, elliptical in shape, with pointed tips. The flowers are beautiful, white, have double petals and yellowish centers.
This dwarf gardenia is an excellent groundcover that produces small, fragrant double flowers.
botanical-name botanical name G. jasminoides ‘Radicans’
sun-requirements sun requirements Full to Part Sun
hardiness-zones hardiness zones 8-11

Radicans is a dwarf variety of gardenia with a spreading habit that often reaches 2-3x its height. It makes a really wonderful ground cover with small, double-petaled, fragrant flowers.

It is a big bloomer from late spring through early summer, producing a great deal of aromatic flowers.

‘Tahitian Gardenia’

Close-up of Tahitian Gardenia (G. taitensis) in bloom in a sunny garden. The plant has long branches covered with large, oval, glossy green leaves. A large, pinwheel-shaped white flower with a warm yellow glow in the center.
Tahitian Gardenia is a unique species that produces delightful pinwheel-shaped white flowers.
botanical-name botanical name G. taitensis
sun-requirements sun requirements Full to Part Sun
hardiness-zones hardiness zones 10-11

This one bears mentioning a second time, as it is a unique and beautiful species of gardenia. Growing up to 10’ tall, Tahitian Gardenia is one of the largest varieties.

The flowers are white and shaped like a pinwheel with a warm yellow glow in the center. It is used medicinally, and cosmetically, and beautiful necklaces are made from its fragrant flowers.

Pests and Diseases

Gardenias are met with a handful of challenges when it comes to pests and diseases. They are particularly prone to powdery mildew. As with their finicky nature, the prevalence of pests is simply outweighed by the presence of gardenia’s enchanting flowers.

Whiteflies

Close-up of a whitefly on a green leaf. The whitefly is a tiny insect that resembles moths and has 4 powdery white wings.
These garden pests feed on the sap of the plant and leave behind honeydew that promotes the spread of mold.

Whiteflies are tiny little insects that resemble moths. They are closely related to scale and aphids. When a plant infested with whiteflies is disturbed, the insects will flutter about, making themselves obvious. Whiteflies feed on plant sap and leave behind an excrement called honeydew.

In addition to stunting the growth of the plant, sooty mold can grow on the honeydew, which interrupts the plant’s chlorophyll production.

Whiteflies can be controlled with horticultural oils or insecticidal soap. Make sure to water your gardenia well before applying these agents as they will cause stress on a plant that is suffering from drought.

Japanese Wax Scales

Close-up of leaves infested with Japanese Wax Scales insects in the garden. The leaves are large, oval, with slightly pointed tips, dark green, glossy. Scale insects are small, oval-shaped insects covered with a sticky, white, waxy coating resembling a dunce cap.
You can get rid of this type of scale insects with the help of garden oil.

Japanese wax scales are one of several types of scale insects that feed on gardenias. Like whiteflies, they feed on the plant’s sap and leave behind their sticky excrement which forms mold and can attract other insects like ants and wasps.

The worst thing about scales is that they are protected by a waxy coat which is impervious to most treatments. Horticultural oil will dissolve the wax and suffocate scales.

There are also natural predators, such as ladybugs, which can be introduced into the garden to feed on the bad insects.

Aphids

Close-up of an aphid infested leaf. Aphids are soft-bodied, tiny insects with light green oval bodies. These insects suck the juice from the leaves.
The main symptoms of an aphid infestation are curled, shriveled leaves and the spread of sooty mold.

Aphids are another tiny insect that likes to suck the sap out of just about any plant in the garden. An infestation of these guys will likely result in curled and shriveled leaves, as well as that black sooty mold that grows in the wake of their destruction.

You may find these little pests clustered underneath the leaves of your gardenia, where they tend to hang out in groups.

Aphids have lots of natural predators that help keep their populations to a minimum. If you see ants show up though, you need to get rid of them, or they will protect the aphids from other predators. A strong stream of water will dislodge most aphids, and insecticidal soaps and oils can be helpful in controlling a bad infestation.

Root Rot

Close-up of a yellowed gardenia leaf surrounded by dark green leaves. The leaves are large, oval, evergreen, glossy, slightly covered with dust. A couple of leaves are turning yellow due to probable root rot.
Root rot occurs due to poor drainage and over watering.

This disease is caused by several fungal agents observed in gardenia plants, the most common being Phytophthora. Root rot can present as a general lack of health in the plant as a whole, or even on one side and not the other.

Other symptoms of root rot are yellowing of the leaves, starting with the oldest leaves, as well as leaf drop and wilt.

The only way to know for sure if the issue is root rot is to dig up the plant and examine the roots. If the feeder roots are brown and weak, your gardenia is probably facing root rot. Root rot is usually the result of poorly draining soil or overwatering.

Prevention is the best way to handle root rot. Make sure that you place your gardenia in a spot with good drainage, and always examine the roots of a new plant before putting it in the ground or a pot. If you have poor drainage in your area in general, planting in a raised bed can help.

Stem Canker

Close-up of a thin tree trunk infected with stem cancer. There is an oval-shaped ulcer on the trunk, with dark brown rotten spots.
This fungal disease occurs in the form of ulcers on the stems of the plant.

Stem canker is another fungal disease that is caused when the fungal pathogen Phomopsis gardinae enters the plant through wounds. The canker develops and eventually can develop a gall. These fungal spores are carried by water, and they can overwinter in the plant, making them difficult to deal with.

Plants found to have stem canker should be disposed of, and new plants should not be planted in the same area. The best prevention of this disease is proper gardening hygiene.

Make sure to always clean your tools before cutting into a new plant. Cross-contamination between plants can ruin a garden quickly.

Bud Drop

Close-up of a withered gardenia bud surrounded by bright green leaves in a garden. The gardenia bush is lush, composed of erect branches covered with evergreen, glossy, dark green leaves, oval in shape. The bud is double, consists of dry orange-brown petals.
The plant drops buds due to stress from disease or insect infestation.

Bud drop is a collective name for any stress that causes the plant to drop its buds. This can be the result of a fungal or bacterial disease, as well as an infestation of insects. Over-fertilizing is another culprit of bud drop.

Powdery Mildew

Close-up of a leaf infected with powdery mildew. The leaf is large, oval, dark green in color, covered with a gray-white powdery coating.
Powdery mildew appears as a white powdery coating and spreads in high humidity.

This disease is caused by the fungus Erysiphe polygoni. It’s unfortunately quite common in gardenias. The fungus typically manifests as a greyish-white powdery coating on the tops of the leaves, especially new growth. This issue usually worsens during the hot summer months, and it can lead to the deformation of leaves and buds.

Humidity is a major factor in the prevalence of powdery mildew. Taking care to prune away dead branches and thin out any crossing branches in the interior of the plant will help to prevent it.

Proper spacing will also make a world of difference, as crowded plants tend to harbor more fungal-related diseases. Fungicides are also an effective preventative measure.

Final Thoughts

While they are not without their issues, a happy gardenia is a sight to behold, not to mention the amazing smells they give. These stunning evergreen shrubs make a wonderful focal point, privacy hedge, or patio plant.

With a little TLC and a bit of extra attention, gardenia plants handsomely award their owners with the most wonderfully fragrant blossoms imaginable.

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A close-up reveals the beauty of a blooming white gardenia flower, its delicate petals glistening with moisture. Behind the flower, the vibrant green leaves stand out, also displaying a moist appearance. In the blurred background, glimpses of other lush green leaves create a serene setting.

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