Beloved for their intoxicating fragrance and attractive, waxy, creamy-white flowers contrasting beautifully with their shiny, leathery, dark green leaves, Gardenias are irresistible heat-loving evergreen shrubs or trees. Native to the tropical and subtropical regions of Africa, southern Asia, Australasia and Oceania, Gardenias are not the easiest shrubs to grow, but their exquisite fragrant flowers make up for the extra attention they require.
Gardenias are beautiful subtropical plants which may be fussy and quite temperamental in their cultural needs. To grow them with success, make sure you follow the below requirements.
- Select a site with full sun to light shade. Although a Gardenia plant prefers full sun, some shade is appreciated during the warmer months of the year or its leaves may scorch and its buds may fall off if they get too much sunlight. In hot climates, Gardenias grow best with morning sun and afternoon shade. In cooler areas, they can tolerate full sun, especially if their roots are covered with organic mulch. Gardenias growing in containers need bright light or filtered shade with no direct sun. Gardenias grown indoors should receive at least 6-8 hours of direct sunlight through a sunny window.
- Make sure your Gardenia soil is moist and well-drained. Gardenias need at least 1 inch of rain (or equivalent watering) each week. Keep the soil consistently damp but not soggy. Don't let the soil dry out and don't over-water your Gardenias or the flower buds will not open and may even drop off. Apply a 2-4 in. layer of organic mulch (5-10 cm) to maintain the soil moist and keep a constant soil temperature. In order to drain away excess fertilizer salts in the soil, water with distilled water once a month.
- Gardenias prefer acidic soil with a pH between 5.0 and 6.0. Avoid planting gardenias near a concrete wall or foundation where the pH may be too high for an optimum growth.
- Gardenias like soil that is rich in nutrients. Add plenty of organic matter to the soil such as peat moss or manure to enhance the growth of your plant.
- Gardenias perform best in day temperatures of 65-70°F (18-21°C) and night temperatures of 60-65°F (15-18°C). Flower buds will fail to form if the ideal temperature for Gardenias is not respected!
- Gardenias demand high humidity to thrive. Provide extra moisture with daily misting, set the plant on a tray of moist pebbles and/or use a humidifier. Extra humidity is important in keeping down spider mites that thrive under dry conditions.
- Fertilize Gardenias every 2-4 weeks during their growing season (March to October) with a dilute fertilizer for acid-loving plants. Do not fertilize from November to February.
- Cut off the faded Gardenia flowers, just below the leaf node, to encourage continuous blooming.
- Check regularly for white flies and mealybugs, using a horticultural oil or insecticidal soap to control these pests.
- Prune/shape your Gardenia plant when it is dormant, to promote branching and compact growth
- When transplanting Gardenias, use a soil mixture of two parts peat moss, one part sterilized houseplant potting soil, and one part sand or perlite.
- Propagate Gardenias in early spring with 3-4 in. (7-10 cm) stem cuttings just below a leaf node. Dip the end of the stem cuttings into a rooting hormone, place it into a light mix of soil with perlite and keep it moist. Transplant the rooted cuttings into 3 in. (7 cm) pots with the preferred growing mix as described above.