The best way to propagate a burning bush plant is by soft-stem cuttings.Burning bush is a deciduous plant that has green leaves in the spring and summer that turn bright red come fall. It is hardy in zones down to USDA zone 3.
Soft-wood cuttings differ from hard-wood cuttings only by time of year. You want to make sure you are cutting the current year's growth. Hardwood cuttings are done in the fall on plants that develop their next season's growth after the growing season. Softwood cuttings are done on plants that put out new growth in the spring. The best time to take softwood cuttings on burning bush plants is in late May or early June, just as the new wood is starting to harden. Take the cuttings too early, and they will die.
Clip cuttings from the tip of the new growth, making sure your cutting is about four inches in length. Take no more than one cutting from each branch. Strip the bottom leaves off the lower two-thirds of the stem until just a stem and a few leaves remain. Scrape the bottom 1/2 inch of the stem gently with a knife to "wound" the cutting. This will help encourage root formation. Treat the cutting with root hormone, poke a hole in the sand, and put the cutting in coarse sand. Do not use potting soil. You want the water to run quickly through the sand so that the new plants don't rot. Space cuttings about one inch apart and firm the sand around them to avoid air pockets.
Keep the cuttings in the shade for the first seven to ten days. Then move them to a sunny spot that gets partial shade. Water them lightly, several times a day. The more often you can water during the early weeks, the better. Even better, use an intermittent mist system to make sure the sand doesn't get completely dry.