Gardenia: Planting, Care, Pruning, Watering

Description and botany

The Gardenia is a shrub from the Rubiaceae family, native to Asia and South Africa. It is frequently found in the wild, on the edges of subtropical to tropical forests. The genus includes about 200 shrubby and evergreen species, but only Gardenia augusta (synonymous with G. florida, G. grandiflora and G. jasminoides, the most common species with an intoxicating jasmine fragrance) and its numerous American cultivars are commonly grown in our latitudes. Occasionally, Gardenia thunbergia can be found, which can grow up to 5 m tall and has spiral-shaped flowers.

It forms rather slowly into a small shrub with greyish bark and a bushy, supple and graceful habit, measuring between 60 cm to 2 m in height in our gardens but can reach up to 12 m in its natural habitat for some rare species. The Gardenia has a very long lifespan.

On rather flexible branches blooms, with rare elegance, the foliage, most often a glossy, varnished dark green. It is sometimes streaked with white (‘Veitchiana’). Oval, elliptical or lance-shaped, the leaves are 5 to 15 cm long, opposite or arranged in whorls of three or more around the stem. Entire, thick, leathery, evergreen, with very prominent veins and sometimes slightly wavy, they provide a dense and permanent green backdrop against which the flowers stand out.

Gardenia jasminoides – botanical illustration

Its sumptuous and very extended flowering throughout summer, with a floral, deliciously intoxicating fragrance, is its major asset. From May to September, pure white to ivory cup-shaped flowers appear, most often solitary or gathered in small cymes at the leaf axils, at the tips or along the branches. If conditions allow, some gardenias like ‘Veitchiana’ can continue to flower in winter, from January to March.

With a waxy texture, each flower opens into a silky corolla of 5 to 12 lobed petals, spreading 4 to 8 cm in diameter. They can be single (Gardenia ‘Kleim’s Hardy’), semi-double (Gardenia jasminoides ‘Summer Snow’) or fully double (Gardenia jasminoides ‘Crown Jewel’). The Gardenia thunbergia has tubular flowers with petals spirally overlapping.

They emit a floral jasmine fragrance, intense and voluptuous.

This evergreen shrub is planted in the ground, in partial shade, sheltered from scorching sun and drafts. Quite demanding, it only thrives in acidic soil, free from lime, fresh, fertile, light and well-drained, as well as in humid atmospheres. Of all climates, it prefers a mild, well-watered oceanic climate.

There are now quite hardy gardenias (down to -10°C to -12°C maximum in well-drained soil), capable of surviving in the ground during our not-too-harsh winters. In colder regions, the gardenia will be grown in large pots to be stored in winter, sheltered from severe frosts, like orangerie plants in an unheated conservatory or cold greenhouse.

Evolution of a Gardenia jasminoides flower.

Main species and varieties

There are many species and varieties of gardenias, but only Gardenia jasminoides, the Cape Jasmine (synonyms Gardenia augusta, G. florida, G. grandiflora) with its intoxicating jasmine fragrance and its numerous American cultivars are commonly grown in our gardens. In recent years, hardier hybrid gardenias (-10°C to -15°C), such as ‘Kleim’s Hardy’ or ‘Crown Jewel’, have emerged, making it possible to grow gardenias outdoors in the ground in our mild-climate gardens.

The Most Popular

Gardenia jasminoides Kleims Hardy

A new variety, as floriferous and fragrant as the species type but hardy down to -12°C!

• Blütezeit June to November
• Höhe bei Reife 80 cm

See the product sheet

Gardenia jasminoides Crown Jewel - Cape Jasmine

Surprisingly hardy for a Gardenia. It has the particularity of being hardy down to -10, -12°C! Perfect for adorning a terrace.

• Blütezeit June to October
• Höhe bei Reife 1 m

See the product sheet

Our Favourites

Gardenia jasminoides Summer Snow

This is the largest of the hardy gardenias! It withstands temperatures down to -15°C and shows rapid growth. It's an exceptional plant that deserves a prime spot in a large pot on the terrace or near the house, under a window or by the entrance.

• Blütezeit June to August
• Höhe bei Reife 1,10 m

See the product sheet

Gardenia jasminoides Perfumed Petticoats

A hardy hybrid gardenia, resistant down to -8/-10°C, medium-sized, with highly fragrant double blooms. It's easier to grow than other hardy varieties. Absolutely stunning on a terrace!

• Blütezeit June to October
• Höhe bei Reife 75 cm

See the product sheet

Planting

Where to Plant a Gardenia

Growing gardenias isn’t always straightforward, so it’s best to respect their rather delicate nature. It’s entirely possible to grow gardenias in the ground, but only in regions where frost is very rare. They clearly prefer climates with warm summers and mild, humid winters (from southern Brittany to Biarritz) as they cannot tolerate frost.

Like camellias, with which they share similar requirements, these somewhat tender shrubs can withstand brief, light frosts down to around -12°C (sometimes lower), but only south of the Loire, in very well-drained soil and in a sheltered spot away from draughts. The hardiness of gardenias varies depending on the duration of frost and soil moisture levels. Elsewhere, it’s best to grow them in pots that can be moved to a cold greenhouse in winter.

Plant them sheltered from cold, drying winds to improve their hardiness and help them cope with frost. Position gardenias in a partially shaded bed or where they’ll receive morning sun, protected from scorching sunlight, which can damage their foliage and flower buds. However, they need plenty of light to flower well, so avoid direct sun during the hottest part of the day.

Plant your gardenia sheltered from cold winds, against a well-exposed wall, such as an east-facing one.

They thrive in fertile, acidic, well-drained soil that stays cool in summer. They dislike lime, so plant them alongside ericaceous (acid-loving) plants. They tolerate dry conditions very poorly, as well as excessive moisture, especially in winter, which will almost certainly cause root rot. While they handle heat well, water them regularly during heatwaves to maintain a humid environment.

In the garden, they’re perfect planted beneath large deciduous trees, which naturally provide the shade and drainage gardenias love. They’ll thrive even more when protected by a wall or hedge. They rarely exceed 1.5m in height at maturity, making them ideal for small gardens. Gardenias pair beautifully with other ericaceous plants like hydrangeas, pieris, kalmias, and rhododendrons.

This delightfully fragrant shrub deserves a prime spot on the patio, close to the house in a well-frequented area, where its sweet blooms can perfume the air.

When to Plant a Gardenia

Plant gardenias in the ground, ideally in spring, in May, once all risk of frost has passed. Autumn planting from September to November, after the peak heat, is also possible.

How to Plant Gardenias

In the ground

Gardenias need a well-draining, humus-rich substrate. Provide deep, light soil, acidified with ericaceous compost and some river sand, coarse gravel, or clay pebbles to improve drainage. Plant them in groups of 2 or 3 per m² for a striking display in borders. A single plant can create a lush effect, especially when mixed with other evergreen foliage. When combined with other shrubs, space them 50cm apart. Ensure good drainage (their roots dislike waterlogging) with a 20cm layer at the bottom of the planting hole.

• Soak the root ball in a bucket for a few minutes
• Loosen the soil to a depth of 25-30cm
• Dig a hole 3 to 5 times wider than the root ball
• Add a layer of pumice, peat, and gravel to the hole
• Plant the shrub level with the soil surface
• Enrich the soil with ericaceous compost, dried leaves, or river sand
• Backfill, firm gently, and water thoroughly after planting, then whenever the soil dries out during the growing season

Growing Gardenias in Pots

In pots, they dislike overly dry or stuffy conditions: maintain good ambient humidity and avoid placing them near radiators or in direct sunlight. Gardenias thrive in greenhouses or conservatories kept between 12–18°C but can be moved outdoors in summer, sheltered from draughts.

• Plant in a mix of ericaceous compost, indoor plant soil, and leaf mould
• Place clay pebbles at the pot’s base
• Stand the pot on a tray of water-filled pebbles
• Position in bright, indirect light

→ Learn more about planting and caring for potted gardenias in our guide

Gardenia jasminoides ‘Kleim’s Hardy’ grown in a pot.

Maintenance, Pruning and Care

This shrub offers an abundant flowering each year, from spring to late summer… provided you give it a little attention and the right care. Whether in pots or in the ground, the gardenia requires very high ambient humidity to thrive.

In the ground

Water only with rainwater (it dislikes lime), without flooding the plant. Mist the foliage during hot spells but avoid wetting the flowers, as this discolours the blooms and causes spots on the leaves.

Every year, in spring and autumn, spread a thick layer of organic mulch (pine bark or needles, leaf litter) to keep its roots cool in summer and warm in winter.

If heavy frost is forecast, cover the aerial parts with horticultural fleece.

In winter, reduce watering to about once a week.

It requires regular feeding to support its flowering: in summer, apply acidic fertiliser for gardenias, specific for ericaceous shrubs, every fortnight. You can also incorporate compost or ericaceous fertiliser annually or biennially by lightly scratching it into the soil around the base.

Gardenia in pots

Water once or twice a week in summer with rainwater or spring water. Allow the soil to dry out between waterings. Place the pot in bright, indirect light, away from radiators, on a tray of water-soaked clay pebbles or gravel. In winter, watering every two weeks is sufficient. Apply a liquid acidic fertiliser for gardenias once a month.

In colder regions, move it outdoors during the warmer months and protect it from frost in winter by placing it in a greenhouse or conservatory.

Each year, top-dress in spring with a mix of compost and ericaceous soil. Repot every 2 to 3 years in late winter or early spring to ensure healthy growth: repot using a mix of compost and ericaceous soil or a special gardenia potting mix.

Pruning gardenias

Pruning the gardenia after flowering helps maintain a neat, compact shape.

• Lightly trim (by one-third) stems that disrupt symmetry
• Remove dead wood
• Deadhead spent flowers

to prevent exhausting the shrub and encourage better blooms the following year

Diseases and potential pests

A gardenia grown indoors will be more susceptible to diseases and attacks by parasitic insects. When planted outdoors, frost and excessive winter moisture are the main enemies of this tender shrub.

Aphids, scale insects and grey mould are the gardenia’s principal adversaries.

Colony of aphids and some scale insects on a Gardenia leaf.

In case of an aphid infestation, remove the colonies by spraying the plant with water or washing the foliage with soapy water.

Use rapeseed oil sprays to smother scale insects.

Avoid hard water at all costs as it causes leaf yellowing and promotes chlorosis.

Sometimes flowers drop before even blooming, likely due to insufficient humidity: mist the leaves with soft water.

→ Also read our advice sheet: Gardenia Diseases and Pests.

Propagation

It is entirely possible to propagate a gardenia by cuttings in early spring.

• Take cuttings approximately 8-10 cm long
• Remove the lower leaves, keeping only the top pair
• Dip the cutting in rooting hormone
• Plant the stem cuttings in pots filled with a moist mixture of peat and river sand
• Place the cuttings in a warm (18–20°C), bright location without direct sunlight and with high humidity
• Keep the substrate slightly moist until rooting occurs, after about a month
• Plant the young plants in the garden the following spring

Pair

The gardenia is the star of shaded gardens, bringing light and sophistication with its profusion of delicate flowers. As a striking focal point or mixed with other shrubs in mild climates, it easily complements any setting.

A planting idea for acidic soil: Azalea ‘Ho Oden’, Pieris japonica ‘Debutante’, Hydrangea macrophylla ‘Etoile Violette’, Gardenia jasminoides ‘Crown Jewel’, Choisya ‘Apple Blossom’ beneath a Magnolia liliflora ‘Nigra’.

Exceptionally floriferous, it maintains a bushy habit with green foliage, making it a beautiful shrub for woodland edges. In heather beds, it pairs well with complementary shrubs that boast equally remarkable blooms, such as Rhododendrons, Pieris, Japanese Azaleas, Kalmia latifolia, Magnolias, Mexican Orange Blossoms, Deutzias, Camellias, and Hydrangeas, which will precede or follow its flowering period.

The densely flowered masses of gardenia will appear lighter alongside a magnificent Japanese maple with delicate, feathery foliage in soft green or deep red. It also pairs beautifully with plants featuring less dense foliage, such as Summer Heather ‘Spring Torch’, Ferns, and ornamental grasses.

Another shaded planting idea: Acer palmatum ‘Dissectum’, Carex oshimensis ‘Everillo’, Gardenia jasminoides ‘Crown Jewel’, Cyrtomium fortunei var. clivicola, Calluna vulgaris ‘Spring Torch’.

This evergreen shrub keeps a touch of green in the garden throughout autumn and winter. Planted at the back of a bed with other gardenias, it creates stunning floral displays all summer.

In pots, the gardenia makes a charming decorative feature year-round. It harmonises beautifully with the abundant blooms of Camellias and Japanese Azaleas.