Plant cloning is a method of plant propagation. Cloning methods use a part of a mature plant to create a new, genetically identical plant. Common cloning methods include division of the root ball, rooted cuttings, and grafting. This method of plant reproduction has been used by horticulturists for thousands of years. Many plants use self-cloning as an additional method of reproduction, along with self-seeding.
Propagation by plant cloning creates a genetically identical plant because only a single parent plant is involved. In contrast, propagation from seeds creates genetically different offspring. When a seed is pollinated, genetic material from two parent plants, or two genetically different areas of the same plant, is combined. When the seed germinates, the resulting plant is similar but not identical to the parent plants.
Many woody shrubs and some herbaceous perennials are commonly propagated by stem cuttings. Depending on the time of year and the maturity of the plant used, the stem cutting may be called a softwood cutting, a hardwood cutting, a semi-hardwood cutting, or a herbaceous stem cutting. Some familiar plants that are commonly propagated from stem cuttings include roses, willows, azaleas, camellias, ivies, spruces, and hollies. Cloning plants using the stem cutting method is used as a reliable, and often fast, method of plant cloning for hybrid and common garden shrubs.
Propagation by grafting is commonly used when growing fruit trees. Many fruit trees do not reproduce identical, or even similar, fruits when planted from seeds. Though the seeds may come from delicious fruits, the resulting tree will likely produce fruits that are quite different in flavor, size, and texture. Common fruit trees that are propagated by grafting include apples, pears, cherries, peaches, plums, most citrus trees, and avocado trees.
Grafting is a method of plant cloning that joins the fruiting part of one tree onto the roots of another tree. A young tree, often grown from seed or cuttings, is used as a rootstock for a cutting from a tree that produces desirable fruit. If the graft takes, the resulting tree will have the roots of one tree and the branches and fruit of another tree. In order to be successful, most grafts are made with similar types of tree — apples grafted to apples, pears, and other similar fruits, while citrus trees are best grafted to other citrus trees, and avocados to other avocados.
Root division is a plant cloning method used to propagate herbaceous perennials and bulbs. In the fall or spring, the roots are dug up and divided into sections. When replanted, each section creates a new, genetically identical plant.
Bulb propagation create offsets, or small bulbs that develop from the main bulb. When dug up and replanted, the new plants are clones of the parent plant. Some plants, such as aloe, agave, and bananas, create offsets, or "pups," above ground near the base of the parent plant. These small clones can be dug up and replanted.
Plants clone themselves naturally all the time in the wild. Perennial plants send out underground or aboveground runners, for instance. Bulbs create offsets underground that increase the size of the plant colony as well. Additionally, cacti and some succulents can drop a leaf on the ground; as the leaf lays there, roots form and gradually grow into a clone of the parent plant. Likewise, a woody shrub or tree may drop a branch that lays on the ground and takes root.