Knowledgebase

Evergreen windbreak and privacy screen. #679081

Asked January 12, 2021, 9:06 PM EST

We are looking to replace a line of 30+ year old blue spruce that have needle blight. We live on a busy intersection and wish to maintain the wind/noise/privacy screen they provide. We were considering plantains a line of new evergreens about 10 feet further behind them back toward the street (still 20-40 feet from the corner). Ideally we could let the blue spruce die naturally while the new line grows and matures, so we are hoping for a tree variety that won't pick up the blight nearby. Would it be better to chop down the existing trees and start fresh? The site is on a southern facing slope and has clay soil. What varietal stands a good choice of living there?

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.

Diane M Replied January 14, 2021, 11:57 AM EST

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