Extension Educator, Horticulture
It's hard to ignore something that slaps you in the face the minute you walk outside. The wind demands our attention. You can always pick out someone from a rural area or from Chicago by their expert maneuvering at leaning into the wind.
Unless Jupiter is your dream place, windbreaks are important here in the Prairie State. Windbreaks reduce heating costs of homes, reduce soil erosion and make living on the prairie more enjoyable for people and wildlife.
Planting a few trees here and there is always a good idea, but an effective windbreak should be planned and placed properly to give maximum benefit and reduce problems. A good windbreak will give protection to a distance approximately 8-10 times its height. Most evergreen trees will get to 40 to 80 feet tall.
To minimize the piling of snow on buildings and driveways in winter, the windbreak should be set no closer than 50 feet from buildings or travel lanes and 100 feet is even better. One or more rows of multi-stemmed shrubs such as redtwig dogwoods planted 50 to 100 feet away from the windbreak on the windward side (outside) will reduce the snow deposited on the leeward side (inside) of the windbreak. This row of shrubs is referred to as a snow tripper. It will allow you to move the primary windbreak closer to areas requiring protection.
Ideally evergreen windbreaks consist of three rows of trees with the middle row alternating between the outside rows. A two row windbreak will still give good results if space is limiting and certainly one row is better than nothing. The rows should be at least 14 feet apart and the trees should be 14 feet apart in the rows. For a quick cover, spacing can be eight feet apart and every other tree removed as they fill in. A great idea someone once told me was to use the removed trees as Christmas trees.
The standard design is an L-shape with the bend pointing to the northwest, which is the direction for most winter winds in Illinois. In the Champaign-Urbana area, the predominate winds are actually from the west so don't ignore the west leg. A good windbreak will provide protection from more than one wind direction.
When selecting plants for a windbreak or any landscape for that matter, diversity is the key. A windbreak should include at least two to three different species. If a pest or disease attacks the windbreak, at least some of the trees will remain. Right now the misguided trend is to plant windbreaks of nothing but white pines. I believe this is a real mistake and asking for future problems.
One row should include a dense species such as Norway, white or Colorado spruce or douglasfir. Pines can be used but they are not as dense as spruce and tend to thin out with age. Additional rows could include white or Austrian pine. Scotch pines are not recommended due to problems with pine wilt disease. In small areas arborvitae or red cedar can be useful. Keep in mind most evergreens do not tolerate wet, poorly drained areas.
Arborvitae, douglasfir and Norway spruce are the only common evergreens to show tolerance to wet soils.The interior or leeward rows could include smaller shrubs or flowering trees to add diversity and to attract wildlife. Evergreen trees make a beautiful backdrop for crabapples or redbuds. Hazelnut, witchhazel, winterberry, arrowwood, or blackhaw viburnum and redtwig dogwood attract wildlife and are lovely additions to a landscape.
For more information contact the U of I Extension - Champaign County Unit at 217-333-7672 for the brochure Windbreak Design and Planting.
Don't forget to sign up for the Master Gardener program.