Angel trumpets, or brugmansia, are exotic, long-lived South American perennials that are hardy to USDA zone 9. These plants thrive in climates with warm and humid days and cool nights. You can propagate angel trumpets from seeds or from cuttings, which are easy to grow. You can also clone cultivars.
Clip semi-ripe wood tip cuttings from a mature, healthy angel trumpet plant when the plant is actively growing. The cuttings should be 6- to 8-inch-long stems that are beginning to change from green to brown, and about 3/8 of an inch thick.
Strip the stems of buds and all but the uppermost set of small leaves.
Place the fresh cuttings in 2 or 3 inches of distilled water in a clear glass or plastic jar. Distilled water is preferable because it doesn't contain impurities found in tap water. Use a permanent marker to draw a line on the container indicating the starting water level. Set the cuttings in a warm location with plenty of bright, indirect light.
If the humidity level is low, create a bubble over the top of the container with a clear plastic bag secured by a rubber band. Poke a few holes in the bag to provide adequate air circulation.
Change the water each day or every other day. Keep the water level consistent with the line on the container.
Plant the cuttings in individual pots when new leaves develop and the roots are several inches long, typically in two to four weeks.