How to Prune a Blackhaw Viburnum
- 1). Sharpen the edges of the pruning tool blades. Hold the blade at a 20-degree angle and swipe it over a sharpening file 10 to 15 times. Sharp tools work better and help prevent injury to the plant. Clean cuts close faster and produce less chance of pathogen introduction than squashed or torn cuts.
- 2). Prune Blackhaw Viburnum with hand pruners after the plant has finished blooming. The plant blooms on last season's growth, which needs to be removed so new growth can take its place. The new growth will be the source of the next season's flowers.
- 3). Remove with hand pruners any dead or broken wood. Cut out any suckers that have arisen at the base of the trunk. Remove the lateral shoots to 1/4-inch from the trunk. Cut out this growth from 12 inches up to 2 feet from the ground. This will produce an attractive tree effect.
- 4). Thin out the canopy of the plant. Remove any non-producing wood and stems that have already produced flowers. Blackhaw Viburnum is a slow-growing plant, which means minimal pruning will be needed annually. It usually is not necessary to do it every year and will preserve the fruits for winter.
- 5). Rejuvenate a neglected or old Blackhaw Viburnum by cutting out the oldest one-third of the wood. Remove it down to the originating wood. Cut only wood that is being removed. Cutting into the originating wood may cause damage. Similarly, trim off one-third of the crown to lower the height. Cut these pieces to within 1/4-inch of the parent wood.