How to Prune a Dwarf Blue Spruce
Since blue spruce trees are sensitive to pruning, Ron Smith of North Dakota State University recommends hiring a certified arborist to prevent damage to your tree.
The blue spruce, also known as the Colorado blue spruce, can reach heights up to 85 feet with a crown width of up to 30 feet. Unless you have a lot of land to work with, a full-size blue spruce may not be ideal for your property. Like full-size blue spruces, a dwarf blue spruce produces distinctive blue-gray needles on its branches but only grows to a maximum height of 10 feet with a crown width up to 5 feet. Even with its limited growth, it may sometimes be necessary to prune a dwarf blue spruce for health and to keep the tree the size you desire.
Avoid pruning a dwarf blue spruce unless absolutely necessary. According to North Dakota State University, evergreen trees, and especially blue spruce trees, cannot survive severe pruning, so never cut the branches on a dwarf blue spruce back by more than 1/4 of the length at any one time. If you must prune a dwarf blue spruce, do so during winter when the tree experiences less growth.
Remove dead wood only if it poses a threat. Like most trees, wood that dies on a dwarf blue spruce eventually breaks off and falls on its own. This form of removal is safe for the plant as long as it won’t potentially hit people, animals or vehicles when it falls. If the dwarf blue spruce is in an area of your landscape where dead wood does pose a risk, cut dead branches off right at the trunk, just on the outside of the thick ring, or collar, at the base of the branch.
Maintain the size of a dwarf blue spruce by pruning the tree a little each season. Cut branches of the tree back by up to 1/4 of the length with clippers to reduce the tree’s overall crown size. Repeat this pruning method each dormant season to maintain the size of the blue spruce and eliminate the need for more drastic pruning later.