The gardenia is an evergreen shrub that flourishes in temperate to tropical environments. The shrub grows to a height of 2 to 15 feet and forms a mound of dark green foliage. Heavily fragrant, waxy white single or double blossoms appear on the shrub from March to June. Gardenias produce tiny red berries following flowering, but the berries are extremely bitter and inedible. Numerous cultivars are available.
Plant gardenias in moist, well-drained soil that is high in organic matter. The soil pH must be between 5.0 and 6.5 for the shrub to flourish. Add peat moss, aged manure or leaf debris to the soil at the time of planting at a ratio of 50 percent organic matter mixed with 50 percent peat moss. Gardenias also grow successfully in containers. Avoid planting gardenias close to coastal areas where the salt is high.
Choose a location that offers full sunlight or partial shade. Avoid planting gardenias near foundations or concrete walkways because the concrete can easily render the surrounding soil alkaline and less than ideal for a gardenia shrub to successfully grow in. The planting location should offer good air circulation for maximum blossom production and to combat fungal infections.
Apply 3 to 4 inches of mulch around the gardenia to prevent weed growth and keep the soil moist. Gardenias enjoy moist soil conditions that are not water-logged. Regular watering is important. The gardenia is not a drought-tolerant shrub. The gardenia also flourishes in humid environments. Many gardenias grown as houseplants do not do well because of the low humidity inside the home.
Fertilizer the gardenia using a well-balanced plant fertilizer for acid-loving shrubs. Apply according to the directions on the label in March, June and September.
Prune the gardenia moderately to maintain its shape after the shrub ceases blooming and prior to October. Pruning should never be drastic on a gardenia.