Gardenias, also known as cape jasmine, are evergreen shrubs commonly grown for their large, white, fragrant flowers. Gardenia plants are popular for forming perimeters around gardens or as hedges, due to their thick, attractive foliage. Gardenias typically reach about 6 feet in height and bloom during the summer. They can be grown either indoors or outdoors, depending on the climate in the region. Gardenia plants are an easy way to add colour and fragrance to any home, lawn or garden.
Planting Site and Temperature
Plant gardenia in a location that receives six to eight hours of direct sunlight per day. Ensure the soil composition is fertile and well-drained prior to planting. Spread 2 inches of organic compost over the planting site and use a garden tiller to incorporate it into the soil to further increase fertility and drainage.
Plant gardenias outdoors in regions where the temperature does not drop below -6.67 degrees Celsius during winter. In regions where the temperature does drop below this point, plant in a container so they can easily be transferred indoors during cold weather. Gardenias thrive at a constant daily temperature of 21.1 to 26.7 degrees Celsius and an overnight temperature of about 15.6 degrees Celsius.
Watering and Mulching
Water gardenia plants only when the top inch of soil is dry, about once every four days, during the first month of growth. After the first month has passed and the plant is established, reduce watering to only when two weeks have passed with less than 2 inches of natural rainfall. Gardenias are drought tolerant, and only need occasional watering to survive. Water indoor gardenias once a week to keep the soil from drying out completely.
Spread a 2-inch layer of mulch over the soil surrounding outdoor gardenias to increase the moisture retention of the soil and suppress weeds. Organic mulches such as pine straw, grass clippings or hay are ideal. Allow about 3 inches of space between the base of the plant and the layer of mulch.
Fertilising and Pruning
Feed gardenia plant twice per year using a balanced 10-10-10 NPK fertiliser. Apply once in early spring and again in late summer at a rate of 1 tablespoon per foot of height. Water the plant both before and after applying the fertiliser to prevent root burn. Do not apply more fertiliser than directed or the plant will produce more foliage than blossoms.
Prune gardenias immediately after flowering ends. Cut off any branches that are excessively long to keep the plant compact and aesthetically pleasing. Remove any damaged or weak limbs to conserve nutrients and increase air circulation to the inner portions of the plant.