The gardenia is an evergreen shrub that grow from 2 to 15 feet tall. Although the dark green foliage is attractive, the plant is grown for its flower, a white, fragrant bloom that appears in the spring. Gardenias grow well in Florida's warmth and humidity and can be used as accent plantings, hedges and container specimens on the patio. The only place in Florida that gardenias will not thrive is along the coast as they are highly salt-intolerant.
Plant the gardenia away from the house as gardenias require good air circulation. Keep it away from any concrete areas as concrete can leech lime from the soil. The gardenia should be planted in full sun or dappled sunlight
Test your soil's pH with a test kit. Gardenias need a pH from 5.0 to 6.5 to avoid mineral deficiencies.
Pour a 3-inch layer of compost over the planting area, and, using the gardening fork, mix it into the top 8 inches of soil. Add the soil amendments you need to raise or lower pH and mix those to the same depth.
Dig a hole that is the same depth at which the gardenia is currently growing and twice the diameter of its root bal, using a shovel. Remove the gardenia from the pot without disturbing the roots. Place the roots into the planting hole and fill halfway with soil. Fill the hole with water and, when it drains, finish filling the hole with soil. The water helps settle the soil around the roots.
Build a watering ring encircling the gardenia. Mound up soil to a height of 5 inches and form it into a ring 8 inches thick. The ring should be placed 1 foot from the gardenia. Each time you water, you'll fill the watering ring.
Pour a 2-inch layer of mulch into the watering ring and spread it around the gardenia. This will help keep the soil moist and the roots cool during the hotter days in the Florida summer.
Fill the watering ring with water two times a week for the first six weeks after planting. After that, cut back the frequency to once a week. When the gardenia is in bud, it is especially important to water the soil consistently to keep it moist.
Fertilize the gardenia in February and October if you live in southern Florida and March and September if you live in the north. Because soil in Florida is generally potassium-deficient, horticulturists at the University of Florida suggest applying a granular fertilizer containing 30 to 50 percent slow-release potassium.
Prune the gardenia with garden shears after it finishes blooming, but before October. The plant doesn't need major pruning, just enough to keep it to the desired shape and size.