It is easy to create new plants for free by propagating the shrubs in your own yard. Collecting seed pods as they dry and taking cuttings from the branches are only two of the ways new shrubs may be created from mature plants. The rose of sharon (Hibiscus syriacus), also known as althea, is not only easy to grow, it is also one of the easiest shrubs for the home gardener to propagate.
Combine one-half general-use potting soil with one-quarter sand and one-quarter vermiculite, mix well. Scoop mix into sterile flowerpots or other containers. Water soil well and set aside to drain while you prepare the cuttings.
Take 6- to 8-inch cuttings from a mature rose of sharon shrub in the late spring or early summer. These should be softwood cuttings, meaning they are still flexible. Cut at a slight angle. Trim away all but the top three leaves. Locate the bottom nodes on the cutting, and, with a gentle touch, scrape around that area with pruning knife. Wounding the cutting will allow it to root more quickly.
Using a small branch, pencil or even your finger, place a hole in the soil about 3 inches deep. Dip the cutting in water and then into the rooting hormone. Place the cutting into prepared container. Press and firm the soil around cutting to remove all air pockets from the soil. Spray the cutting with fine mist of water from sterile spray bottle.
Place the straight branches in soil at the edge of pots so that they are taller than the cuttings by 2 to 4 inches. Cut a large enough piece of plastic to cover the pot and secure it with rubber band or garden twine at bottom. Poke a few holes in the plastic. Doing this will create a mini-greenhouse to give the new cuttings a good start.
Check cuttings daily for moisture. Never allow cuttings to dry out. Roots will appear in two to three weeks. Remove the plastic tent and place in location that is sunny with shade in the hottest part of the day until ready to transplant. Transplant into larger pot when roots begin to fill up the small pot and leave in the larger pot until the following spring.