With respect to C. florida, Cappiello, "Dogwoods; The Genus Cornus", (2005) has this to say: "Softwood cuttings treated with 8,000 to 10,000 ppm IBA can root between 50 and 85 percent if the timing is just right." "Rooted cuttings should remain undisturbed through the dormant season to achieve maximum success."
