How Long Does It Take Rosemary Cuttings to Root?

Division and Layering

• Rosemary plants naturally produce roots wherever their stems touch the ground. In the low-growing, or prostrate, varieties of rosemary, you'll see numerous points where the stems have rooted as they creep along the ground. In this case, a rooted stem can easily be clipped from the parent plant and transplanted immediately. In upright varieties, the stems are less likely to be in contact with the soil, but they can be made to root just the same. In this method, called layering, soil is hilled up around the base of the plant on one side to encourage roots to form. If the area is kept moist, substantial rooting should occur within two months and the stem can be clipped off and transplanted.

In a Pot

• Rosemary cuttings will also root if potted in perlite or a lightweight potting soil mixture. All but the topmost leaves should be stripped off to prevent moisture from leaving the plant material through transpiration. Cuttings should be made from the mid sections of the stems just above where the wood is brown and hard, but not from the growing tips where the wood is too soft and supple. A typical cutting is about 4 to 6 inches long. If these guidelines are followed and the cuttings are kept moist and away from direct sunlight, they will develop roots within a month.

Misting House

• The ideal set-up for propagating rosemary is a misting house. A misting house is like a tiny greenhouse outfitted with misting nozzles. The idea is to create an environment with 100 percent humidity that prevents the desiccation of plant material before the roots have formed. Once the cutting is rooted, it is able to absorb water on its own and can be removed from the misting house. Perlite is used as a rooting medium in misting houses because of its ability to hold water and air, and allow the growth of tiny rootlets. In a misting house, rosemary will begin to form roots within one week and will be ready to transplant after three weeks.

Stick Cuttings

• Rosemary cuttings can also root if stuck directly in the ground. The key to this method is to do it in the cool weather of fall. The success rate will be lower than with the other methods, but if adequate moisture is maintained, at least some of the cuttings will form roots and grow into new plants. For this method, it is appropriate to take slightly larger cuttings from the older wood lower down on the stem. Stick them into a bed of loose soil and allow four to six months before transplanting in the following spring.