Acer, or maple trees, are some of the most popular shade and specimen trees available to homeowners. A. platanoides is the Norway maple, and crimson king maples are a cultivar of Norway maples. Crimson king maple trees are planted for their burgundy-to-purplish summer foliage, their aggressive growth and their tolerance of air pollution and neglect. For the most part, crimson king maples don't require a lot of pruning. Prune the trees once or twice while they are young to develop a strong structure and shape, or for their health when they have broken or damaged branches.
Pruning Young Crimson King Maple Trees
Plant crimson king maples in early-to-mid spring. Consider the mature height and width of the tree when choosing the planting site. Plant trees where they will not eventually grow to interfere with electrical wires or overhang houses to avoid pruning. Complete the initial pruning the day that the tree is planted.
Prune crimson king maples that are between 1 and 6 years old in early spring just before bud break. This will allow you to see the tree's structure without obscuring leaves. Pruning before growth starts also allows your tree to seal pruning cuts faster due to the aggressive growth of spring.
Make cuts just outside the branch collar (the raised area of bark where the branch connects to the tree). This allows the tree to grow bark over the pruning cut; cutting inside the branch collar can leave an open wound that heals poorly, leaving the tree susceptible to insect damage and disease. The pruning cut will usually seal over in one growing season.
Stand on a ladder or use an extendable pruning saw if branches are higher than your chest. It is easier, and safer, to cut branches with saws that are chest high or lower. Doing this also puts less stress on your chest, arms and back.
Use hand or pruning saws for branches that are thicker than 1 1/4 inches. Use a chain saw for branches that are thicker than 5 inches.
Remove branches that cross or rub against other branches. These branches typically grow in towards the crown and need to be removed to give your tree a symmetrical shape.
Remove branches that have a narrow or weak crotch (emerge from the trunk at an angle 30 degrees or less).
Remove broken, diseased and dead branches as soon as you see them.
Pruning Mature Crimson King Maples
Prune your crimson king maple minimally to keep it healthy after it is 6 years old. Pruning for aesthetics (the shape and symmetry) should be complete once the tree is 6 years old.
Hire a professional arborist to remove branches that are more than 24 feet high. Professionals have access to cherry pickers and safety equipment, and can prune mature trees without causing irreversible damage.
Remove broken and diseased branches as soon as you see them.