Location: Spring Valley, CA
Question: I would like to know the best method to propagate bougainvillea and the best time of year for a successful propagation.
Answer: Bougainvillea can be propagated by stem cuttings or by layering. Both are easy to do; the only difficulty you might encounter is that the plants resent having their roots disturbed, so you'll have to be especially careful when transplanting your rooted cuttings. You can take semi-ripe cutting in mid- to late-summer, or hardwood cuttings in mid-winter. Both require warm, humid conditions (65F-70F degrees). Summer cuttings are current season's growth that has begun to mature and stiffen up. You should see some bark beginning to form on the stem. Cut a 6-8 inch length of stem, strip all but a few leaves from the cutting, dip cut end in rooting hormone, and place in a pot of moistened growing medium. Half sand and half commercial potting soil works well. Place the pots in a greenhouse, cloche, or coldframe, out of direct sunlight. The covering will help retain soil moisture and keep the cutting from drying out. When new leaves appear along the stem you'll know that roots have formed. Hardwood cuttings are current season's growth that has matured and developed bark. Follow the same guidelines as for semi-ripe cuttings. To propagate by layering, you need only to bend a growing stem down to the ground and anchor it. Find a stem that's producing new growth, bend it down until it touches the ground, nick it slightly on the lower side, bury the injured stem part in the soil, and anchor it with bent paperclips or a stone. Layering should be started in the spring when the plant is growing vigorously. Check in late summer to see if roots have developed. Once they have, you can cut the stem from the parent plant, dig the rooted part out and carefully plant it in its new location.