Extension Educator, Horticulture
This time of year I'm never quite sure what to write about. Poinsettias? Christmas trees? Snow? But then it hit me. Yes, literally hit me. It's hard to ignore the wind as it slaps us in the face the minute we walk outside. I'm surprised we don't all have a perpetual forward lean to our walk.
Unless Jupiter is your dream destination, 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 8 feet apart and every other tree removed as they fill in. Use the removed trees as the family Christmas tree.
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 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 survive. Presently the misguided trend is to plant solid windbreaks of white pines. In my mind this is a major mistake plus white pine hate extremely windy areas.
One row should include a dense species such as Norway, white or Colorado spruce or douglasfir. With some added irrigation in drought periods these will grow fairly fast. Pines can be used but they are not as dense as spruce and tend to thin out with age. Additional rows could include a few white or Austrian pine. Scotch pines are not recommended due to their susceptibility to pine wilt disease. In small narrow areas yew, red cedar or the preferred choice arborvitae can be useful. Keep in mind most evergreens do not tolerate full shade or wet, poorly drained areas. Yew and Canadian hemlock tolerate some shade but are best left to less windy 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 such as crabapples or redbuds to add diversity and to attract wildlife. Hazelnut, witchhazel, winterberry, arrowwood, or blackhaw viburnum and redtwig dogwood attract wildlife and are lovely additions to a landscape.