   Growing Plants from Cuttings - October 23, 2002 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Most gardeners have been given a plant shoot by a friend and rooted it to produce a new plant. The scientific term for this process is "asexual propagation". Asexual propagation includes growing plants using cuttings, layering, plant division, grafting, and tissue culture. Each plant derived as a result of asexual means is genetically identical (a clone) to its mother plant. It should have the same leaf shape, flower color, fruit characteristics, growth form, vigor, and so on, as the parent plant from which it was grown. In nature, asexual propagation is fairly common. Some local examples are: cottonwoods, willows, creosote, agaves, cactus, some grasses, manzanita, several noxious weed species, and many others. Most plants also reproduce through sexual means as well. Sexual propagation is important to maintaining a certain level of genetic diversity within a given plant species. Without this diversity, environmental conditions could change and the plant species would not have the ability to adapt to those changes. For practical purposes, lets review some of the practices that will increase your success in growing cuttings. Always take cuttings with a sharp blade to reduce injury to the parent plant. Dip the cutting tool in rubbing alcohol to prevent transmitting diseases from infected plant parts to healthy ones. Remove flowers and flower buds from cuttings to allow the cutting to use its energy and stored carbohydrates for root and shoot formation rather than fruit and seed production. To hasten rooting, increase the number of roots, or to obtain uniform rooting (except on soft, fleshy stems), you should use a rooting hormone, preferably one containing a fungicide. Prevent possible contamination of the entire supply of rooting hormone by putting some in a separate container for dipping cuttings. Once cuttings are made, they must be placed into a growth medium such as coarse sand, vermiculite, soil, water, or a mixture of peat and perlite. It is important to choose the correct rooting medium to get optimum rooting in the shortest time. In general, the rooting medium should be sterile, low in fertility, drain well enough to provide oxygen, and retain enough moisture to prevent water stress. Moisten the medium before inserting cuttings, and keep it evenly moist while cuttings are rooting and forming new shoots. Some plants prefer warm soil. Commercial operations often do this by heating the propagation beds. Most cuttings need to be placed in bright, indirect light to successfully grow roots. Greenhouses really work well for cuttings. Tip cuttings are also commonly used in production nurseries. Here, a 2 to 6-inch piece of stem, including the terminal bud is cut off the mother plant just below a node. Remove lower leaves that would touch or be below the rooting medium. Dip the stem in rooting hormone if desired. Gently tap the end of the cutting to remove excess hormone. Insert the cutting deeply enough into the media to support itself. At least one node must be below the surface. Once rooted, plant the cutting in a clean pot preferably filled with sterile potting soil. If you are new at this, start out with geraniums, succulents, or cactus. In many species, researchers are still attempting to unravel the mysteries of asexual propagation with varying levels of success. I once supervised a tissue culture lab for Simpson Timber Company in Blue Lake, California. We grew redwood and Eucalyptus (both of which reproduce in nature through asexual means). We were working on a method to culture Douglas-fir but were never successful. Asexual propagation is fun and reward in the home garden. I encourage everyone to try it: especially children. The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/. |