I have it in a narrow space and want to make it columnar.... How to prune??? thanks kerry
Pruning a Diablo Ninebark
Kerry, you are trying to put a round, arching plant into the wrong space, I'm afraid. Ninebark looks and flowers best when allowed to form arching stems that reach the ground. It is a fast grower and you would have to prune it at least twice a year to keep it columnar. This will remove many of next year's blooms. If you give it a try, prune out the oldest wood to the ground after it blooms in spring. Trim wayward stems back to a lateral shoot that is growing in the direction you want. Consider growing red-twig dogwood, Cornus servicea. It can be pruned almost to the ground in early spring to contain the size and keep the twigs a brilliant red. This is one dogwood that does not have significant flowers so trimming in summer or early fall isn't a problem.