Evergreens for sound barrier and beauty

Asked August 7, 2015, 1:26 PM EDT

I find that traffic has increased in front of my yard, have some evergreen trees but need more. Which varieties of evergreens, are best. I would like to plant a variety to add interest as well as acting as a sound barrier.

Olmsted County Minnesota

1 Response

Thank you for the question. According to the University of Alabama Extension Service, vegetation with solid barriers can reduce highway noise by 6 to 15 decibels. You probably don't have a sound barrier wall in your landscape so you'll want a thick barrier, like a hedge, dense and tall enough that you can’t easily see through or over for the best result. The effectiveness is multiplied by planting vegetation in multiple rows and multiple tiers, such as an over story of tall trees, an understory of tangled shrubs, and a ground cover. If you want to really increase the effectiveness of your sound barrier, an earthen berm constructed several feet high and wide, with plantings atop and around it, can diminish noise by a third or half the perceived loudness. From Extension.org, the key points to consider when creating the most effective noise barrier with vegetation:

  • Planting depth is a greater than 75 to 100 feet
  • Planting height is at least 18 to 20 feet
  • Vegetation is densely planted
  • Combinations of evergreen and deciduous trees and shrubs are used
  • Different layers of vegetation are used
  • Vegetation is planted close to the noise source

Before selecting plants, evaluate your site for light exposure and soil conditions along with the amount of space for mature plants. Planting trees or shrubs is a major physical and financial effort. You want to stack the odds for success by planting the right plant in the right spot. Read this publication on how to assess your site: http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/selecting-shrubs-for-minnesota-landscapes/

Visual appeal is very personal, so you will have to do your homework to decide which plants you like the best and that match the plant growth conditions with the site growing conditions. The following link has a great chart with the kinds of evergreens that grow well in Minnesota along with their maximum height and width. Arborvitae, mugo pine and junipers will all stay short enough for most power lines if they are part of your landscape. Arborvitae and junipers come in different shapes and colors which can definitely add an interesting backdrop.

Thank you for contacting Extension.