The gardenia is an evergreen flowering shrub, native to tropical areas of Africa and China. A member of the coffee family, gardenias bloom from May to July with fragile, highly scented flowers. Because of its stringent temperature requirements, the gardenia is a difficult plant to grow indoors.
Provide bright light but no direct sunlight. Temperatures need to be kept on the cool side, between 55 and 65 degrees F. At no time should temperatures be allowed to get cooler than 55 degrees F or warmer than 70 degrees F.
Gardenias thrive in an acidic soil, so the potting soil should be amended prior to planting. Mix together equal parts of potting soil, peat moss and sand, moisten it with water and allow it to drain before planting your gardenia.
Water the gardenia well and don't let it dry out. Keep the soil very moist. Although gardenias require high humidity, misting with water may cause damage to the leaves. Instead, fill a tray or pan with pebbles and then with water until just the tops of the pebbles are exposed. Place the plant on top of the pebbles. Make sure that the pot doesn't sit in the water. Add more water to the pan as it evaporates making sure to keep the tops of the pebbles exposed.
Apply a gardenia or an azalea fertilizer, according to package directions, in March, July and November. Gardenias and azaleas have similar soil pH requirements.
Prune your gardenia after it has finished blooming. Make the cut just above a leaf joint.
Inspect the gardenia for mealybugs, aphids, spider mites and scale. You can control infestations with neem oil, which is available at nurseries.