When the bracts put on their finest holiday hues, it’s hard not to fall in love with poinsettias. Whether you find your favorite in the reds, pinks, icy white, or wildly patterns, these are tropical plants that shout ‘Happy Holidays!’ I am a fan of white poinsettias, but every Saturday morning I am treated to a host of red ones. The atrium inside the building where I broadcast weekly has low walls arranged to guide foot traffic through the vast space. In December the walls are lined with potted red poinsettias all dressed up in foil wrap and ribbon. No matter how gray and rainy the early morning is, their beauty ‘points’ out the glory of the season and warms my heart.
All this often comes to an end along with garlands, wreaths, and trees and poinsettias get tossed into the trash. Too bad, since even a few leaves left on the stems have potential to regrow and in the process, provide cloning material. I would be remiss if I didn’t acknowledge that many, but not all, poinsettias have plant patents clearly stated on their labels. Those that are not can be cloned at will, while the protected varieties must not be propagated for any commercial reason. That means that if you decide to grow poinsettias to decorate the church next year, choose a non-patented variety.
Once you have chosen the color that you want to keep growing, find the right place to put the new mother plant for the long term. In warm winter climates, that may be the sunny porch outdoors. Elsewhere, a heated greenhouse is ideal and next best is a warm sunroom, but I grew a poinsettia for several years in a group under artificial lights. Stuck with a room that had no windows, I lined the walls with light fixtures and plants and frankly, never grew a better bunch of assorted species.
Whether you start with a sad plant or one still in its glory, the first step to propagating poinsettia is to cut the mother plant back. The stems that have already made bracts and tiny yellow blooms have less potential than new growth. Clip off at least 3 inches of stem below the bracts, preferably half of its total length. (I know it’s hard – if the plant looks nice, wait a few weeks to do this and then proceed.) Repotting is not usually needed, but a regular program of water and fertilizer is important. Once the new stems are six inches tall, take four inch cuttings and immediately drop them into a cool place such as the produce drawer of a refrigerator for a day. The chill stops latex flow, stiffens the stems, and improves their condition for rooting. You can clone poinsettias in any clean rooting media, but they are particularly successful in rooting cubes made of oasis (like the floral foam). It’s long been a ‘secret’ that tomato seeds start readily on oasis. To use the classic product, it is necessary to soak it in fertilizer and water, then cut the block into cubes. Thanks to the hydroponic world, better cubes than you can make are readily available. They are denser, more efficient water managers, and already full of nutrients. Roll each stem in Hormex # 3 or dip in Hormex Liquid Concentrate for 1 minute and then slip it into the rooting media or cube.
Professional growers root poinsettias under mist for the first 2 weeks. During that time it is important to keep the leaves hydrated since the stems are busy forming callous and have no roots yet. An alternative is a plastic or glass cover over cuttings but its management is slightly different from most cloning cloches. Instead of opening it daily to ventilate, leave these cuttings enclosed until moisture builds up to obscure your view of them. Air exchange is important but you are advised to keep it to a minimum in this first period. After that, ventilate as needed to keep conditions moderately humid inside the chamber. In about 8 weeks, the poinsettias should be well-rooted and ready to pot up. Another advantage to using cubes is the ability to see roots creeping out the sides and that’s a gift worth giving to yourself!