Kleim's Hardy gardenia

Sun

Morning sun and afternoon shade; light shade in hot climates. In cooler regions, choose a warm, sheltered position with several hours of sun.

Water

Keep the root zone evenly moist but never waterlogged. Water during dry spells, including winter dry spells when the soil is not frozen; containers need more frequent checks.

Soil

Humus-rich, well-drained, acidic soil, ideally pH 5.0-6.0. Use ericaceous potting compost in containers where garden soil is alkaline.

Height

2-3 ft (0.6-0.9 m)

Spread

2-3 ft (0.6-0.9 m)

Flowers

Fragrant, single white flowers with conspicuous yellow stamens in late spring and early summer; occasional later flowers in favourable conditions.

Foliage

Evergreen. Small, glossy, leathery, dark green leaves; foliage may yellow or suffer scorch in cold, exposed conditions.

Growth

Slow to moderate

Care needed

Medium

• Pollinators
• Deer resistant
• Heat tolerant
• Low allergen
• Fragrant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Hard

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   1.6 ft (0.5 m)

2. After 1 year

   1.8 ft (0.54 m)

3. After 2 years

   1.9 ft (0.58 m)

4. After 3 years

   2 ft (0.62 m)

5. After 5 years

   2.3 ft (0.69 m)

About 7 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Growth rate

Slow

• Plant with the top of the root ball level with the surrounding soil; do not bury the stem.
• Water deeply when the surface begins to dry, using rainwater where tap water is very alkaline.
• Apply an acid-loving shrub fertiliser in spring at the label rate; avoid feeding in late summer or autumn.
• Maintain a 2-3 in (5-8 cm) mulch of composted bark or leaf mould, keeping it clear of the stems.
• Shelter from cold, drying winds and protect from severe frost; move containers to a bright, cool, frost-free place where winters are too cold.

Pruning. Prune lightly just after the main flowering period to shorten straggly shoots and maintain a rounded shape. Remove dead wood once new growth shows what has survived winter, and avoid routine autumn pruning, which can remove developing flower buds.

Spring

Plant once severe frost has passed; check drainage and mulch the root zone.

Mid-spring

Feed with an acid-loving shrub fertiliser and inspect new leaves for yellowing.

Late spring

Keep moisture steady as flower buds develop; inspect shoots and leaf undersides for pests.

Early summer

After the main flowers fade, prune lightly if shaping is needed.

Summer

Water during dry spells and take semi-ripe cuttings from healthy, non-flowering shoots.

Autumn

Stop feeding and arrange winter shelter for container plants in cold regions.

Winter

Protect from severe frost and drying winds; keep sheltered container plants slightly moist, not wet.

• Plant beside a sheltered path or seating area where the flower scent can be enjoyed.
• Use in containers on a partly shaded patio, especially where the garden soil is alkaline.
• Repeat along the front of an acidic-soil shrub border for a low, rounded evergreen structure.
• Combine with white flowers and dark foliage in a sheltered white garden or courtyard.

Garden styles it suits: Modern courtyard, Southern, Sensory garden, White garden, Small-space and Traditional.

Plant it with: Azaleas, Camellias, Japanese pieris, Japanese painted fern, Hostas and Mondo grass.

Wildlife: The open flowers provide accessible pollen and may attract visiting insects. Dense evergreen growth offers modest shelter, but this is not a major wildlife food plant.

• Yellow leaves with green veins: often iron chlorosis caused by alkaline soil or water. Check soil pH and drainage, use rainwater, and apply chelated iron suitable for the soil conditions if needed.
• Flower buds dropping: commonly caused by drying out, waterlogging, temperature swings or moving a budding container plant. Keep moisture and growing conditions steady.
• Scale insects or whitefly, sometimes followed by black sooty mould: inspect leaves and stems, remove small infestations by hand, and use a labelled insecticidal soap or horticultural oil if necessary.
• Winter scorch or dieback: shelter from cold winds, mulch the roots and protect during severe frost. Wait for spring growth before cutting back damaged stems.

Gardenias are toxic to cats, dogs and horses if eaten, usually causing mild vomiting, diarrhoea or abdominal discomfort. Keep leaves, flowers and any fruit out of reach of animals that chew plants. Serious human poisoning is not generally reported, but this ornamental is not a food plant and its sap may irritate sensitive skin.

• Double-flowered gardenia (Gardenia jasminoides)

  Many other gardenia cultivars have densely layered, rose-like flowers; 'Kleim's Hardy' has single flowers, usually with six petals and exposed yellow stamens.

• Star jasmine (Trachelospermum jasminoides)

  Star jasmine is a twining climber with smaller, five-petalled, pinwheel-shaped flowers; 'Kleim's Hardy' forms a self-supporting rounded shrub.

• Natal plum (Carissa macrocarpa)

  Natal plum has forked thorns, thicker leaves and five-petalled white flowers, followed by red fruit; gardenia has no thorns.

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

Propagation. Take semi-ripe cuttings in summer and root them in a moist, free-draining medium with humidity and gentle bottom heat. Use cuttings to preserve the cultivar; seedlings will not reliably match it.

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.