Cuttings

Because stems are able to produce adventitious roots, cuttings of stem pieces are commonly planted. This is in fact the preferred method of vegetative propagation. Both herbaceous and woody cuttings are successfully used. The new roots grow on the cut surface of the stem piece. A root-growth promoting substance such as indole acetic acid, naphthalene acetic acid, or a phenoxyacetic acid compound is commonly used. The cut surface of the stem piece is dipped in a powder containing such a substance just prior to planting. The act of cutting may itself produce a wound hormone, which plays a role in producing adventitious roots. Sand and vermiculite are the preferred media for the rooting of cuttings. Very small cuttings are sometimes placed on agar in a petri dish in order to circumvent the problems caused by fungi and bacteria. Leaves or pieces of leaves may be successfully used as cuttings in propagating a certain few species of plants. Begonia, Sansevaria, Kalanchoe, and African violets are all propagated in this way. Rhizomes are planted to increase irises, and strawberries are increased by the use of stolons (stems that grow on the surface).