Use of auxins to stimulate adventitious rooting of stem cuttings is a powerful tool used to propagate many nursery species. When used properly these compounds will: 1) increase the percentage of cuttings which form roots, 2) hasten root initiation, 3) increase the number and quality of roots produced per cutting, and 4) increase the uniformity of rooting.

There are many auxins that can be used to stimulate adventitious rooting but the two that are used most often commercially are indolebutyric acid (IBA) and naphthaleneacetic acid (NAA). In fact, both these auxins, either alone or in combination, are the active ingredients in most commercial rooting formulations although IBA is more effective for a wider range of species.

Commercial rooting products are generally available in two major formulations/preparations. The first of which consists of one or more auxins dispersed in a talcum powder carrier (e.g., Hormodin, Hormo-Root, Rootone, etc.) and the second consisting of one or more auxins dissolved in a solvent (e.g., C-mone, Dip 'N Grow, Wood's Rooting Compound, etc.). The rooting powders are available in a range of concentrations (strengths) whereas the solutions are concentrated and often require dilution prior to use depending on the species or cultivar you wish to propagate. Instead of purchasing commercial powder or liquid formulations, one may obtain the pure form of particular auxins and actually prepare a rooting powder or solution of one or more auxins. However, this can be somewhat difficult which is why the commercial preparations are so widely used.

Individuals will often ask which formulation (powder or solution) is most effective for rooting cuttings of various species. Although both formulations have advantages and disadvantages and can provide satisfactory results if used properly, the solutions are generally more effective for various reasons. The powders are best used on stem cuttings of herbaceous (nonwoody) plants (e.g., coleus, chrysanthemum, and geranium), woody species which are not difficult to root (e.g., boxwood, Japanese holly, and forsythia), and softwood cuttings of woody species which are relatively easy to root (e.g., Atlantic white cedar and 'Green Giant' arborvitae).