Choose cuttings from the soft new growth of an established plant, use hormones to encourage rooting, plant cuttings in well-drained seed starting mix and keep cuttings moist to propagate rosemary successfully. Most growers prefer propagating rosemary from cuttings because it is difficult to grow from seed.
Obtain a cutting by snipping a piece of new growth about 2 inches long off a healthy plant. Remove the leaves from the bottom inch and dip the exposed section in a rooting hormone. Plant the cutting in moist, sterile seed starting mix. A product that contains peat moss with perlite or vermiculite is ideal because it allows adequate drainage. Stand the container in a warm place out of direct sunlight. Don't allow the soil to dry out, and mist the plants daily. After two to three weeks, gently pull on the cuttings to check whether they have roots. If they do, transplant them into pots with diameters of 3 to 4 inches or directly into the garden in a frost-free region. Rosemary thrives in sandy, well-draining soil and requires six to eight hours of full sun. Ensure that rosemary planted in a container does not bake in the sun but receives adequate light. Pinching off the top of cuttings encourages the plants to develop branches and spread.