Growing in the wind

Western red cedars create an effective windbreak. Photo/Illustration: courtesy of Tim Boland

When planning a windbreak, I pay attention to plant spacing to ensure that trees aren’t planted too closely or too far apart. Trees planted too closely together quickly create a bar­rier but may lose their lower branches due to excessive shade. Trees planted too far apart leave openings that may funnel the wind. Research the mature heights and widths of trees before buying or planting to save money and to help you develop a better windbreak. And be wary—nurseries sometimes recommend closer spacing in an attempt to sell more trees.

When designing a windbreak, avoid planting a monoculture. Using just one species of a tree can cause problems later if a disease or insect chooses to make trouble. Instead, plant three to five of one tree species, then alternate with three to five of another species. Plant an odd number of trees in staggered rows, placing the tallest into the prevailing winds, followed by progressively smaller trees. Because these trees buffer strong winds, choose ones with full bodies and lower branches that do not die off as they mature.

Numerous evergreen species are available, and many have cultivars with attractive forms and foliage colors. Perhaps the most admired evergreen tree at the Polly Hill Arboretum is the Japanese cedar (Cryptomeria japonica ‘Yoshino’, USDA Hardiness Zones 6–9). This is a fast-growing conifer that maintains a strong central leader and has beautiful shiny green foliage. Another impressive evergreen is the Western red cedar (Thuja plicata and cvs., Zones 6–8), a handsome tree with lustrous green foliage that retains its lower branches even when mature. It also exhibits good resistance to deer.

Shrubs and ornamental grasses can also be used as effective wind barriers. The North American native arrowwood viburnum (Viburnum dentatum, Zones 3–8) forms a full-bodied shrub with a dense branching structure that has good wind resistance. A prairie grass known for its wind tolerance and longevity is the aptly named ‘Northwind’ switchgrass (Panicum virgatum ‘Northwind’, Zones 5–9). In several ornamental grass trials, ‘Northwind’ tops the list for its ability to remain upright while with­standing wind, snow, and ice. Through careful selection and planting, you can work with all nature has to offer, including strong winds.