Greetings. I have 4 Blue Spruce trees all next to each other. The 15 year old...

Asked March 27, 2014, 12:37 PM EDT

Greetings. I have 4 Blue Spruce trees all next to each other. The 15 year old tree looks great. The two 25 year old trees seem to each have a classic case of Rhizosphaera . The 22 year old tree has something else. It has several branches that are completely brown, along with a crown that has lost its needles. Are antifungal efforts worth the effort? what would you do? Thanks!

Dakota County Minnesota

1 Response

25-30 years is about the average life span for a Colorado Blue spruce in MN. They are not well adapted to our hot, dry summers. If it is rhizosphaera and this should be confirmed before any treatment, the tree can recover. If these trees were a favorite in my landscape or would be if healthy if treated I would at a minimum find out what it would cost to have them treated. Then I would look at them again and see if they are worth it. I might also want to keep them until replacement trees (that are not Blue Spruce) had a chance to grow and have a bigger impact on the landscape or view. The links included in this email may be helpful in deciding what to do.
If you do keep the trees for a while longer, mulch under the trees and make sure they get adequate water all summer and fall. MN long dry falls create problems for trees. They need moisture until the ground freezes.

http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/spruce-tree-diseases/rhizosphaera-needl...
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/spruce-tree-diseases/
http://www.ag.ndsu.edu/cpr/forestry/needle-cast-diseases-of-spruce-diagnosis-and-treatment