Gardenia

Sun

Morning sun and afternoon shade suit most gardens. It tolerates more sun in mild coastal climates, but hot afternoon sun can scorch leaves and flowers.

Water

Keep the root zone evenly moist, not waterlogged. Water during dry spells and check containers frequently in warm weather; reduce watering during cool winter conditions.

Soil

Acidic, humus-rich, moisture-retentive but well-drained soil, ideally pH 5.0-6.0. Use ericaceous potting mix in containers where garden soil is alkaline.

Height

4-8 ft (1.2-2.4 m), with many compact cultivars remaining smaller

Spread

4-8 ft (1.2-2.4 m)

Flowers

Mainly late spring and summer, sometimes repeating into autumn in warm climates; white, strongly fragrant flowers age to cream or yellow and may be single or double.

Foliage

Evergreen. Glossy, leathery, dark green leaves, usually in opposite pairs or groups of three.

Growth

Slow to moderate

Care needed

High

• Water at soil level before the root zone dries out completely; do not leave pots standing in water.
• Feed with a fertiliser for acid-loving shrubs in spring and, if needed, early summer, following the label rate.
• Apply 2-3 in (5-8 cm) of bark or leaf-mould mulch, keeping it clear of the stems.
• Use rainwater for containers where tap water is hard and alkaline.
• Shelter from cold winds and protect container plants from frost; avoid hot, dry indoor air.

Pruning. Prune lightly just after the main flowering flush, shortening straggly shoots and removing dead or damaged wood. Avoid heavy pruning in autumn or winter, which can remove developing flower buds.

Spring

Plant once frost risk has passed, or refresh the surface compost of established container plants.

Spring

Apply acid-loving shrub fertiliser and renew mulch.

Summer

Check soil moisture frequently and inspect leaf undersides for pests.

Summer

After the main flowering flush, prune lightly and take semi-ripe cuttings.

Autumn

Stop feeding and move tender container plants into bright, frost-free shelter before cold weather.

Winter

Keep sheltered plants lightly moist, with good light and ventilation; avoid standing water.

• Plant beside a terrace or entrance where the flower scent can be enjoyed at close range.
• Use matching containers to frame a doorway or sheltered courtyard.
• Combine with camellias, azaleas and ferns in a sheltered, acidic-soil border.
• Use as a low evergreen hedge in mild climates, allowing enough space to avoid frequent clipping.

Garden styles it suits: Southern, Modern courtyard, Romantic rose garden, Sensory garden, White garden and Tropical.

Plant it with: Camellias, Azaleas, Japanese pieris, Hydrangeas, Hostas and Ferns.

Wildlife: Single flowers can provide pollen and nectar for visiting insects; densely double flowers are less accessible. The evergreen foliage offers some shelter for small garden wildlife.

• Yellow leaves with green veins: often caused by alkaline soil or water making iron unavailable. Check soil pH and drainage, use rainwater where possible, and apply chelated iron suitable for the soil conditions.
• Bud drop: commonly follows drying out, waterlogging, sudden temperature changes or moving a plant in bud. Keep moisture and growing conditions steady.
• Scale insects, whiteflies or spider mites: inspect stems and leaf undersides. Treat with insecticidal soap or horticultural oil labelled for the pest and plant, avoiding hot sun and open flowers.
• Root rot: encouraged by saturated soil or pots standing in water. Improve drainage, empty saucers and remove badly affected plants.

Toxic to cats and dogs if eaten, usually causing mild vomiting or diarrhoea; all parts should be kept out of reach, particularly the fruits. It is not known to be toxic to horses. In people, ingestion may cause mild stomach upset, and contact can irritate sensitive skin.

• Crape jasmine (Tabernaemontana divaricata)

  Usually has pinwheel-shaped white flowers and milky sap; gardenia does not produce milky sap.

• Cape jessamine (Gardenia thunbergia)

  Typically has single flowers with a conspicuously long, narrow tube and large, hard, woody fruits.

• Star jasmine (Trachelospermum jasminoides)

  A twining climber rather than a self-supporting shrub, with smaller pinwheel-shaped flowers and milky sap.

Gardenia honours the Scottish-born physician and naturalist Alexander Garden, while jasminoides means jasmine-like, referring to the resemblance of its flowers.

Propagation. Take semi-ripe, non-flowering shoot cuttings in summer and root them in a free-draining medium with warmth and high humidity. Seed is slower and does not reliably reproduce named cultivars.

Accepted botanical name

Gardenia jasminoides

In the US and Canada

Introduced in Pacific Basin and Puerto Rico.

Native range

Cambodia, China North-Central, China South-Central, China Southeast, East Himalaya, Hainan, Laos, Taiwan, Thailand and Vietnam.

Measured

Average height 300 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.