Lilacs are durable, long-lived shrubs that can thrive in nearly any climate as long as they get at least 8 hours of sunlight per day. Versatile shrubs, lilacs can be planted as a hedge or along a fence, as a background for other blooming plants or in an open area where the lovely purple or white blooms can take center stage. Propagate a lilac bush by taking a stem cutting in late spring.
Fill a planting container with a mixture of half coarse sand and half perlite. Be sure the container has bottom drainage. Set the container aside while you prepare the softwood cutting.
Cut a softwood stem from a healthy lilac tree using a sharp knife or garden pruners that have been wiped with rubbing alcohol. The stem should be 4 to 6 inches long, and the cut should be made just below a leaf node, which is where a leaf or bud grows from the stem. A softwood stem will break with a sharp snap when you bend it. If the stem bends without breaking, it's too young. If the stem is so large that it won't bend, it's too mature.
Strip the leaves from the bottom half of the softwood cutting. Dip the cut end in rooting hormone, and plant it in the potting mixture. Be careful not to scrape off too much of the rooting hormone. Water the potting mixture to settle it around the cutting.
Put a piece of clear plastic over the container, or cover the container with a clear plastic bag. Put a few stakes or a piece of bent wire in the container to keep the plastic from touching the leaves.
Place the container in indirect sunlight. Avoid direct sunlight, as the sun magnified through the bag can be hot enough to burn the softwood cuttings.
Check the container often. If the potting mixture dries out, water it lightly. Don't allow the potting mixture to dry out; keep it just moist but not soggy, which can rot the cuttings. The lilac cuttings should take root within 3 months.
Check occasionally to see whether the cuttings have rooted. Using an old spoon, remove a cutting carefully from the potting soil, check the roots, then replant the cutting. When the roots are a minimum of 1 inch long, plant the cutting in a container filled with equal parts peat moss, topsoil and sand, or an all-purpose commercial potting mix.
Place the young lilac in a shady, protected spot and continue to keep the soil moist. Allow the young lilac to grow for two growing seasons, then plant the bush in its permanent home.