Can Colorado Blue Spruce Be Pruned for Growth?

Time of Year

• Colorado blue spruce trees respond best to pruning when it is performed in late winter or early spring as they emerge from dormancy. Prune the branches after a flush of new growth appears but before the wood hardens. Avoid pruning Colorado blue spruce tree once the weather warms to 68 F or above because it will cause permanent damage to the branch and it will put on growth at a different rate than the rest of the tree, creating a lopsided appearance.

Tools

• Use sharp anvil loppers when pruning Colorado blue spruce trees to promote growth because they will cut cleanly through the branches without tearing or splintering the wood. Sanitize the blades beforehand by dipping them in hydrogen peroxide. Let the blades dry completely before using the loppers on the tree. Do not use dirty, dull anvil loppers because they can easily transmit fungal infections such as cytospora canker, which can devastate and kill Colorado blue spruce.

Process

• Prompting thicker growth on Colorado blue spruce trees takes careful pruning because taking off too much growth will permanently damage the shape of the tree and its ability to put on new growth. Inspect each branch to determine where the fresh new growth emerges from the mature wood. Prune the new growth from each branch using the anvil loppers. Make the cut just above a set of stem offshoots to encourage dense branching on the tips, which will give the tree a bushier appearance.

Potential Problems

• Colorado blue spruce trees respond to light pruning, but can easily go into shock if too much length is removed from each branch. Avoid removing more than one-third the total length from each branch. Do not cut or remove the leader, or top vertical branch because it will grow back deformed and will permanently ruin the attractive conical shape Colorado blue spruce trees are valued for.