A thriving lilac that grows in a color you enjoy and at a height you prefer is worthy of cloning to plant more lilacs like it throughout your property or to give to friends and family. By taking cuttings you can clone a lilac bush over a period of months with basic gardening supplies. Plan to collect your cutting in the spring after your existing lilac finishes flowering to give it the most amount of time to root and grow before planting into the ground the following year.
Select an end stem from a young branch along your bush or pick a tender shoot that is sticking up from the ground near the base of the lilac to make your clone. The stem should be 4 to 6 inches in length and no thicker than a pencil.
Cut the stem or shoot from the parent plant using clean pruning shears by making a diagonal cut across the width of the stem. Place the cut end of the stem or shoot into water.
Fill a gallon pot with potting soil for each stem or shoot you have collected. Wet the soil enough to dampen it evenly throughout without making it soggy.
Remove any leaves which are growing out from the bottom half of the cutting using your pruners. Rewet the bottom inch of the cutting with water if it has dried during leaf removal.
Dip the bottom inch of your cutting into a rooting powder, allowing the water to help the powder stick to the sides and cut surface of the stem or shoot.
Push the stem or shoot down into the soil so the cutting is planted halfway down. Gently move the soil around the cutting to hold it in place, but don't pack the soil around the cutting.
Move the pot to a sunny room in your home or greenhouse where it won't be hit by direct sunlight. Water the soil as necessary to keep it moist over a period of six to eight weeks. During this time the roots should grow, but upper growth above the soil may not be seen.
Transfer the pot to a spot with direct sun after you notice the first sets of leaves growing or the cutting has grown in height. Water more heavily to saturate the soil at the bottom of the pot to encourage deep root growth. Continue watering until the following spring and plant it outdoors after the last frost has passed.