Gardenias are subtropical evergreen plants that are well suited to Auckland’s climate. They have pure white flowers, contrasted by their glossy dark green leaves. With a rich intoxicating fragrance, gardenias bloom throughout spring and summer, and they can fit into many garden styles.
Planting Calendar
Gardenias are best planted between September and January.
Prepare
Position
Gardenia enjoy part sun to dappled shade. They will thrive in a warm, sheltered, frost-free position and are great in pots as well.
Soil
When planted into the ground Gardenias likes a acidic free draining soil that is rich in organic matter. To improve the organic content in your soil, break up the soil and add Kings Compost and Kings Sheep Pellets then mix together well. The addition of Peat mixed into the soil and an acid fertiliser will provide the correct conditions for the plants. When growing in containers, plant into Kings Container mix. This mix contains added water storage crystals and Saturaid, two products that help maintain moisture in the soil.
Plant
When planting into the ground, gently tap the plant out of its pot. Dig a hole twice the depth and width of the plants root ball. Mix Kings Compost into your existing soil at a 50/50 ratio, add Sheep Pellets and Kings Azalea, Camellia and Rhododendron fertiliser along with 6 handfuls of peat, then mix together. Back fill the hole with this soil, so that when planted the top of the plant’s roots sit level with the surrounding ground. Firm the soil down gently and water in well with Aquaticus Organic Garden Booster. In heavier clay soils, where drainage is likely to be an issue, plant onto a raised mound and sprinkle Gypsum Clay Breaker into the bottom of the hole, this helps slowly condition the soil and help to break down the clay. When planting into containers plant into Kings Containers mix, as this has water retention crystals in it, which will help in keeping the soil moist. Firm the soil down gently and water in well with Aquaticus Organic Garden Booster. Feed with Kings Slow Release Azalea, Camellia food for acid loving plants.
Care
Watering
Watering is essential especially in the first year of planting to allow the roots to get well established. Water slowly allowing the water to sink down into the roots, rather than allowing it to run off the top of the soils surface. Add Saturaid into the soil at planting as this will help channel the water deep down into the root zone. Consider setting up an automatic watering system – these can be simple and inexpensive.
Feeding
When planted in the ground feed with an acidic fertiliser such as Kings Azalea, Camellia, Gardenia and Rhododendron food as per the instructions on the packet. In addition give them a boost by liquid feeding monthly with Aquaticus Garden Booster, from Spring through to the end of Autumn, this encourages root growth and increases the microbial activity in the soil. Monthly applications of Kings Sheep Pellets will help with soil conditioning and plant health. If growing in containers feed with Kings Slow Release Azalea, Camellia food.
Protecting
Protect you Gardenias from the hot midday sun, as this may burn the leaves or flowers.
Mulching
Mulch around the base of the plants (make sure that the mulch does not come into direct contact with the stem of the plant) with Living Earth More than Mulch. Mulching helps to reduce weeds as well as aiding the soil to retain moisture.
Spraying
Scale, Aphids and Mealy bug are the main pests that affect Gardenias, these can be sprayed with Groventive Garden or for an organic option spray with Bugtrol.
Pruning
Prune after flowering has finished to remove spent flowers and any untidy branches. Prune back either to a branch or a healthy looking bud. Any cuts near a bud should slope away from the bud at a 45° angle.
General Care
When using sprays, chemicals or fertilisers always read the label and follow the instructions. Apply sprays in the evening to avoid harming beneficial insects.
Expert Tip
A deficiency in magnesium, iron or nitrogen will cause chlorosis, this will be evident by yellow leaves, bud drop and lack of flowers. As a tonic, feed with Sequestron for a quick-fix as soon as the foliage starts to turn yellow.
Tip
For rich green foliage, apply a regular dose of Epsom Salts, available instore.
Top Varieties
Gardenia Radicans
A groundcover form that has small leaves and small semi-double flowers, which bloom for longer in warmer climates. Growing 30cm x 75cm
Gardenia Veitchii
A larger growing variety with prolific double white flowers. Growing to 90cm x 90cm
Frequently Asked Questions
Why do my gardenia leaves go yellow?
There are a few different reasons for yellowing leaves, the main reason is lack of nutrients. Feed with liquid acid fertiliser in spring. As flower buds start to form, feed with Sequestron.
Where do Gardenias like to grow and what do I feed them?
Gardenias like to be planted in either full to partial shade and should be protected from the hot midday sun. Feed regularly with Kings Camellia food.
The leaves on my Gardenias are going brown in places, what is causing this?
If your plants are exposed to hot sun, this can cause the parts of the leaves that the sun shines on to go brown.
What is the smallest growing Gardenia?
Gardenia radicans would have to be the smallest growing. It is a ground cover and spread to about 75cm and only gets about 30-40cm high.
