Topiary is the art of creating sculptures in the medium of clipped trees, shrubs and sub-shrubs. MasterDomino has developed a method for this using the Gen3 tree generator script.
I have written a tutorial about how to create tree sculptures with a custom shape and I am demonstrating how to do this on our beloved Suzanne using the Gen3 tree generator script by stager13. The tutorial does not go into detail about the use of the tree script (since there are already tutorials about that) it just explains the steps you have to take after that.
You can find the PDF file link in the BlenderArtists discussion thread.