This past weekend, the time was right to do something I’ve been meaning to try for the past couple of years, namely ground layering a native hydrangea in the woodland garden.Commonly called silverleaf hydrangea, H. radiata is common in the Upstate and other parts of the southern Appalachians. Once considered a subspecies of the smooth hydrangea (H. arborescens), cross-pollination experiments yielded few if any viable seeds and thus most experts now consider it to be a separate species. Though very similar to the smooth hydrangea, the silverleaf is easy to distinguish by its foliage, which is typical on top but silvery white below.
Unfortunately, the silverleaf hydrangea is much more difficult to grow from cuttings than its kin. I hope ground layering, which promotes root growth along a branch without cutting it away from the mother plant, will prove effective. This propagation method has a higher rate of success because it prevents the water stress and carbohydrate shortage that can doom cuttings.
I selected a handful of low branches for my effort. Then, I dug a 3-inch deep trench directly beneath each branch and carefully pinched off four leaves (two pairs of the branch’s opposite facing foliage). Pinching creates small wounds that should stimulate the plant to produce roots at that spot.To complete the process, I covered the wounded area of the branch with native soil topped with leaf mold, and anchored it in place with a heavy stone. I plan to check the branches in about six weeks. If this batch doesn’t take, I’ll try again. Semi-hard branches could be more fruitful and, if necessary, I’ll use rooting hormone to increase my chance of success.