Gardenias provide not only beautiful flowers, but also a gentle fragrance. This shrub grows 2 to 6 feet tall, producing flowers as big as 4 inches wide. But these attractive plants are finicky. The wrong climate or amount of shade, soil or water significantly affects your gardenia's growth and fragrance. Plant outdoor gardenias in slightly acidic soils and in a warm climate.
Plant gardenias in fall or spring in full sunlight or a partially shaded area. They bloom best in a climate where the temperature hovers around 22.8 degrees C during the day.
Plant gardenias in moist, slightly acidic soil. Find out your soil's pH with an at-home testing kit from your local plant nursery. For a small garden, make your soil more acidic by adding a 1- to 2-inch layer of sphagnum peat on top of your soil and working it in 8 to 12 inches deep in the existing soil. Use a hoe to work the peat into the soil.
Water plants at least every other day during the summer. The plant base should remain moist, but not soaked or dry. If you add mulch you will not need to water as often, as the mulch will retain water. Remember to water your gardenias even when they are not in bloom.
Feed gardenias in March and late June using an acidic plant food. Refrain from feeding gardenias during the autumn months because cold weather could damage the resulting new growth.
Prune gardenias when they finish flowering in the late summer by removing dead branches and flowers.
Gardenias do not grow well in the cold; refrain from planting them if you live in a cold climate. Regularly inspect plants for insects and disease. Any irregularities on the leaves could be a sign of disease.