While the gardenia (Gardenia jasminoides) is a staple of Southern gardens, you don't have to live below the Mason-Dixon Line to enjoy the shrub's glossy evergreen foliage and fragrant white roselike flowers. Gardenias grow into shrubs 3 to 6 feet tall outdoors in U.S. Department of Agriculture plant hardiness zones 8 through 12, and you can grow them as houseplants elsewhere. The plants can be short-lived, however, especially indoors, so it always pays to have a backup. Gardenias propagate readily from stem cuttings, so use any prunings to clone new plants.
Water your indoor or outdoor gardenia well the night before you plan to take your cuttings. Cuttings can be gleaned from normal pruning that you would do to shape your plant from early spring for softwood cuttings, through midsummer for semi-hardwood cuttings.
Spray the blades of your bypass pruners with household antiseptic cleaner and dry them with a paper towel. Cleaning the tool helps prevent transfer of disease or fungus from a previously pruned plant to your new cutting or your established gardenia.
Cut several 4- to 6-inch pieces near the top of the shrub from growing ends of the gardenia with your clean pruners. Select stems that are vigorous and have no signs of insect damage or disease. Cut at a 45-degree angle, just below a leaf node.
Strip the leaves from the bottom half of each cutting.
Fill clean flowerpots with an equal mix of moist sand and peat moss. Make holes 2 inches deep in the pot with your fingertip or a pencil -- one for each cutting.
Dip the angled end of the cutting in rooting hormone powder.
Insert the cuttings into the holes -- avoid knocking off the rooting hormone -- and firm the peat/sand mix around the stems with your fingers.
Place two pencils, drinking straws or twigs into the soil to act as props, and place a clear plastic bag over the flowerpot.
Move the pot to an area that has bright, indirect light and is about 75 degrees Fahrenheit. Keep the soil moist for the four to six weeks it takes the gardenias to root.
Remove the plastic and repot each rooted gardenia in its own 4-inch pot filled with the same sand and peat mixture. You can then move the plants to a cooler area in filtered sunlight.