Q. I have a 21-foot Viburnum hedge that is 30-inches wide that I would like to trim out the dead branches. The hedge is 20 years old and I keep it pruned to 36 inches tall. I would like to trim it down to 14-16 inches tall in order to access and remove the dead branches. Is pruning down to 14 inches too severe and is it too hot to do it now?
A. The usual time to prune Viburnum hedges is in the spring after the bloom. You are a bit late, but it will probably do fine if you have access to water for irrigation of the growing hedge plants. Do you think you can prune out the dead pieces and only reduce the height to 24 inches? It would also help to apply some slow release lawn fertilizer (19-5-9) to provide nutrients for the regrowth. If you are not worried about the bloom, you could wait and prune in the winter.