Annabelle Hydrangea (H. arborescens 'Annabelle') is easy to propagate. Softwood cuttings, about 6-8 inches long, taken in May or June and dipped in rooting hormone, root within two weeks. You can rapidly produce a lot of new plants with softwood cuttings. You can also divide your Annabelle. In spring or fall, use a sharp spade to slice down and cut the roots between the main plant and a few of it's outer stems. Slip the division out of the ground and transplant it elsewhere, then fill the hole you've created at the base of the 'mother' plant. Give both your original plant and the new transplant TLC; water if your area experiences a dry spell.