Gardenias are evergreen shrubs with fragrant white or pale-yellow flowers. Here's how to care for your gardenia bush.
- Plant your gardenias in well-conditioned soil containing peat moss and/or compost.
- Add mulch to help keep the soil moist and free of weeds.
- Plant your gardenia where the temperature's between 65 and 70 degrees Fahrenheit (18.3 to 21.1 degrees Celsius). If the weather isn't conducive to growing gardenias, you can plant them in pots, indoors.
- Expose indoor gardenias to bright, indirect sunlight. Outdoor gardenias should have full sun with some shade.
- Water your gardenias, but not too much. Over-watering can cause Rhizoctonia [source: Gardening Central].
- Fertilize your gardenia every two to three weeks with a water-based fertilizer. Add an acid-based fertilizer every few months.
- Prune your gardenia while it's dormant. Pinching the tips at this time promotes a bushier, heavier bloom in the following season [source: The Garden Helper].
- Spray mist around -- but not directly on -- your plant daily when the weather is dry. Gardenias thrive in a humid environment.
The following diseases affect gardenias.
- Canker fungus presents with a swollen stem base and cracks around the canker. If you don't remove dead plants from the soil, the disease will spread. Don't plant anything where the infected plant had been.
- Sooty mold is caused by whiteflies
- Leaf spot presents as brown spots with yellow halos around them. It can be controlled with fungicide.
- Rhizoctonia causes tan-colored spots and is extremely contagious. If your gardenia gets Rhizoctonia, destroy it and sterilize the soil [source: Gardening Central].
Gardenias are also prone to infestation. Get rid of infestation with organic or chemical insecticides. Someone at your local county agriculture extension might have suggestions for dealing with specific pests in your area. Aphids and mealy bugs, among others, are attracted to gardenias [source: Gardening Central].
Finally, if you notice your gardenia is suffering from bud drop it's a sign of either too-cool or fluctuating temperatures, or over- or under-watering.