Taming the Wind
Selected trees and sturdy landscape structures can act as wind barriers in large and medium yards.
Conifers, spruce and pine make excellent 12-month wind barriers. Care should be taken to plant them only in a space where they can grow to their full potential. Although a solid spruce hedge makes a nice windbreak, it's not in the best interest of the plant's health to be planted so close together. Without proper sunlight and oxygen exchange, overcrowded branches become weak and diseased.
At this point the purpose of planting a spruce hedge becomes fruitless. Once the trees are removed, stumps don't block much wind. The same goes for poplars. People are constantly cursing them. It's really not the tree's fault, the blame should be placed on the overzealous "Johnny Appleseed" who planted the tree in the first place.
In my opinion, (other than the cottonwood) poplar trees have a definite place in the urban landscape. The key is knowledge. What species are grown where depends on the situation and long-term needs of the client. Large species such as "Northwest" or "Balsam" poplar make excellent windbreaks for large yards as long as they are planted away from foundations and utility lines. Columnar aspen have a shallow fibrous root system and make excellent windbreaks in smaller yards, they grow roughly six feet high and 30-40 feet tall.
A combination of conifers and deciduous trees not only provide a striking visual contrast, but go a long way to helping to break the wind. The key is to know the characteristics of a given tree and make sure it will meet your long and short-term needs.
In a smaller yard, such as an infill, it may be necessary to construct permanent screens or overhead structures such as arbours or a pergola. Due to limited space, it's not always possible to use trees to help block the wind. These artificial windbreaks can be supplemented with creeping vines or smaller pyramidal conifers that will give some visual relief. All overhead structures should have posts made of a 4x4 inch material or greater
and should be cemented in the ground at a depth of no less than three feet. The overhead structure should be built with materials strong enough to withstand the worst wind gusts in your area. No matter where you live in Alberta, with some creativity and a good knowledge of plants you should be able to "tame the wind."
As a native Calgarian, I welcome the sight of a Chinook arch with mixed emotions. On one hand, the warm temperatures are a nice reprieve from a prolonged cold spell. However, the accompanying warm Westerly winds can wreak havoc on unprotected or unhardy plants.
Edmonton is not known for its Chinook winds, however, I'm sure that some of the hot air that comes from the legislative buildings can be equally annoying. Even during the Summer months, the prairie provinces are well known for their gusty winds.
While it may be great for kite flying, a strong wind can easily spoil an afternoon barbeque on an unsheltered backyard patio, although we can not completely stop the wind, with a little imagination, we can minimize its detrimental effects on the landscape.
In planning a new home, once site orientation has been established, it should be determined where and how the prevailing winds will affect the landscape.
Most winds are from the North or West direction in our regions of the country. The industrial section is located on the east side of most cities, so the winds will not blow the smells and vapours back into the city. One of the first steps in planning a new landscape is to create a suitable micro-climate to fit the needs of your new "mini-environment". On an acreage, this is accomplished with a shelterbelt. This is the planting of different heights and species of trees and shrubs which will provide an eventual windbreak. More specific information about planting a shelterbelt is available through Alberta Agriculture.
Unless mature trees are used at the start, which can be very costly for a large area, a shelterbelt can take up to 20 years to be really effective. What I normally recommend when landscaping an acreage, on a limited budget, is to choose a location close to or protected by the house for your outdoor living space. Perhaps then, part of your landscape budget would be to bring in some mature trees that would give you instant protection from the wind. You could then begin to create your own outdoor paradise that will give you instant enjoyment.
Many new homes are built on sloped lots in areas that are very exposed to the elements, wind included. Many people avoid buying these lots just for these reasons, however, I see these lots as having amazing landscape potential. Granted these sloped lots are more costly to landscape than a flat lot, but the results can be very worthwhile, what better way to avoid wind than to be located below its flight path. A sunken deck or patio can create a warm, cozy, relaxed feeling.
Picture a paving stone patio surrounded by three feet of terraced boulders, softened by colourful perennials and framed by a rough cedar arbour crawling with Virginia creeper or grape ivy. Add a small waterfall trickling into a lily pond and you created an atmosphere that would make even the cast of Gilligan's Island drool.