Question: Should a new Shadbush be pruned to a single trunk or how many branches should be encouraged? Answer: Jonathan Foster, Home Horticulture Outreach Professional Pruning needs depend on what type you have–some species can be trained into a tree shape by pruning to a single trunk, if that’s the look you are shooting for, read more Should a new Shadbush be pruned to a single trunk or how many branches should be encouraged?