Pruning spruce trees with cytospora canker

Asked October 26, 2016, 1:16 PM EDT

I am a member of the landscape committee in a town home association. Our property is surrounded by many spruce trees that are close to 20 years old (mostly Colorado spruce). Several of the trees are infected with Cystospora canker (dead lower branches, purple needles, white/bluish resin on infected branches). A tree expert confirmed C. canker. We would like to do some pruning ourselves. Any tips? Should we have a professional do this?

Washington County Minnesota blue spruce

4 Responses

If the trees are 20 years old, they are no doubt quite tall. So have a professional do it. Get several bids. Seek references. Read here:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/how-to-hire-a-professional-arborist/

Your landscape committee might also consider a long-range replacement plan. Twenty years is about the best we can hope for from Colorado blue spruce in our climate. They might already have rhizosphaera needle cast, another common CBS disease:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/spruce-tree-diseases/rhizosphaera-needl...
So you'd be wise to consider budgeting for replacements now.

We are working on developing a long-range replacement plan. We've been advised to avoid planting more Colorado spruce and to consider Black Hills Spruce instead. Norway spruce and Balsam fir have also been suggested. Are there pros or cons to any of those particular alternatives? Do you have other suggestions? Thanks for your help!

It is a good idea to avoid CBS. They have a lot of problems in our climate. Black Hills spruce is often suggested as an alternative, but they can still get the same disease cluster as CBS. Be sure to give them plenty of room for air circulation, which seems to slow the diseases down. The list you've given suggests you want evergreens. A place to start looking is here:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/recommended-trees-for-minnesota/southea...

You'll find the trees you mentioned plus a few others on that list. I'd also suggest a visit to the Minnesota Landscape Arboretum, where you can see specimens of many of the trees in the document above.

Thank you for the links and suggestions.