The gardenia is beloved by Southern gardeners for its waxy white blossoms and exotic fragrance. However, this plant is very fussy. Your gardenia bush will not blossom properly unless certain conditions are met.
The gardenia is a semitropical, evergreen shrub that grows in U.S. Department of Agriculture hardiness zones 8 through 10. This plant thrives in high humidity and prefers mild daytime temperatures between 68 to 74 degrees F. For buds to form properly, the gardenia requires cool evening temperatures between 40 to 60 degrees.
The gardenia prefers full sun to partial shade and requires at least 4 hours of sunlight daily in order to bloom. It thrives in moist, well-drained, acidic soil. Fertilize your gardenia from March through August with an acidic fertilizer. The Clemson University Cooperation Extension warns that fertilizing in the fall produces early growth that can be damaged by cold winter temperatures.
Bud drop, a condition in which flower buds fall off before opening, is a common problem with gardenias. Bud drop is caused by a number of issues, including inadequate light, low humidity, insect damage and overwatering. Extreme temperature changes — either too high or too low – also cause buds to fall.