Knowledgebase
Evergreen windbreak and privacy screen. #679081
Asked January 12, 2021, 9:06 PM EST
Dakota County Minnesota
Expert Response
Blue spruce trees are certainly beautiful, but as you’ve discovered, they face significant challenges in Minnesota. You’re fortunate that you have space available for additional or replacement plantings to help screen and block noise. Vegetation with solid barriers can reportedly reduce highway noise by up to 6 to 15 decibels, and the effectiveness can be multiplied by planting trees and shrubs in multiple rows and tiers. To be most effective, look for an ultimate vegetation height of approximately 20 feet planted close to the noise source.
You questioned whether the blight can be spread to adjacent trees, and that can occur. Water splashing during a rain can carry the fungus to other hosts. Norway or white spruce seem to be more resistant than other conifers, but you may wish to remove the blue spruce to avoid that contingency. For more information, see
https://www.purduelandscapereport.org/article/blue-spruce-update/
To learn more about needle blight in Minnesota, see https://extension.umn.edu/plant-diseases/lirula-needle-blight, and for detailed information on planting a windbreak or noise barrier, see https://extension.umn.edu/agroforestry/trees-shrubs-windbreaks#conifer-trees-1740463
Because of the scope and potential expense of your project, it is certainly worth obtaining the opinion of a certified arborist. The arborist can assess your particular site and needs and offer helpful advice. See https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional
Good luck with your project.