Gardenia
Grown for its heavily fragrant white flowers and glossy dark foliage, but has a reputation for being fussy, and yellowing leaves are its classic complaint, usually caused by soil that's too alkaline or watering that swings between too wet and too dry rather than by pests. Frost-tender, so it's a realistic outdoor plant mainly in Northland, Auckland and other consistently mild areas; elsewhere it does best in a large container that can be moved under cover over winter.
- Sun
- partial sun
- Water
- moderate
- Spacing
- 90cm
- Difficulty
- intermediate
- Grows in
- Whangārei / Northland, Auckland, Hamilton / Waikato, Tauranga / Bay of Plenty, Gisborne, Napier / Hawke's Bay, New Plymouth / Taranaki, Palmerston North / Manawatū-Whanganui, Wellington, Nelson, Tasman
- Mature height
- 1.5m
- Flowering season
- Jan, Feb, Nov, Dec
- Evergreen
- Yes
- Common diseases
- Sooty mould following aphid or scale infestation
- Common pests
- Aphids, Scale insects
When to plant by region
In Whangārei / Northland, Auckland, Tauranga / Bay of Plenty, Gisborne and Napier / Hawke's Bay: September-November. In Hamilton / Waikato, New Plymouth / Taranaki, Palmerston North / Manawatū-Whanganui, Wellington, Nelson and Tasman: October-November.
Growing stages
PlantingSpring, once frost risk has passed
- Plant into acid, free-draining soil in a warm, sheltered spot; a hard frost can badly damage or kill this plant
- Part shade suits it better than full sun all day, especially in hot inland areas
- Outside consistently mild areas, growing in a large container that can be moved under cover over winter is the safer option
Establishment
- Keep watering consistent; alternating between too dry and too wet is the most common cause of yellowing leaves and bud drop
- Watch for aphids and scale insects on new growth and flower buds
- Feed with an acid-plant fertiliser through the growing season to support glossy, deep green foliage
FloweringSummer
- Sooty mould can develop on leaves following an aphid or scale infestation; treating the pest clears the mould
- Avoid moving the plant or changing its position once flower buds have formed, as gardenias commonly drop buds in response to stress
- Pick flowers in the cool of morning for the strongest fragrance indoors
Maturity & overwintering
- Trim lightly after flowering to maintain a compact shape; avoid hard pruning, which removes next season's flower buds
- In cooler regions, move container-grown plants to a sheltered, frost-free spot for winter
- Yellowing leaves in winter are often just cold stress rather than a soil problem; check both before treating