I bought a cloning machine. A simple device that pumps air into water into which cuttings are suspened. Really easy to root things this way. I have had rapid success with tomato, basil, rose and assorted hardwoods. I am researching for textbooks, how-to manuals or academic papers on this propagation method. I haven't found anthing so far. If you have seen any literature where someone has documented what works and what doesn't with this method, please post a response.