Best known for their fragrant white flowers, gardenias are heat-loving evergreen shrubs that have become a gardening symbol in the Southeast. Another common name is cape jasmine.
About This Plant
Plant gardenias near a deck or window where you can enjoy the flowers’ fragrance. The plants grow from 2 to 8 feet tall and wide, depending on the variety. Most gardenias grow into a round shape with dark green, glossy leaves and white, fragrant flowers that bloom from mid-spring into summer. Avoid planting gardenias near a concrete walk or foundation where the pH maybe too high for good growth.
Select a site with full sun to light shade and moist, rich, well-drained soil. Gardenias prefer acidic soil with a pH between 5.0 and 6.0. In Sunnyvale California, this means you must acidify the soil.
Plant in spring or fall, spacing plants 3 to 6 feet apart. Have the soil tested to determine pH, and if necessary add the recommended amount of sulfur to reduce the pH to between 5 and 6. Dig a hole only as deep as the root ball and 2 to 3 times as wide. If your soil is in very poor condition, amend the soil you’ve removed from the hole with a small amount of compost. Otherwise don’t amend it at all. Carefully remove the plant from the container and set it in the hole. Fill the hole half full with soil, then water it well to settle the soil and eliminate air pockets. Let the water drain, then fill the remainder of hole with soil and water thoroughly.
Gardenias require at least an inch of rain (or equivalent watering) each week. Apply a 2- to 4-inch layer of organic mulch to help keep soil moist, reduce weeding, and maintain a constant soil temperature. Feed monthly during the growing season with an acidifying fertilizer. Prune in early spring to shape the bush, and deadhead after flowering to encourage more flowering. Check periodically for white flies and mealybugs, using a horticultural oil or insecticidal soap to control these pests. In regions where the plant is marginally hardy, protect bushes from hard freezes and drying winter winds.