Current interest in landscaping with native plants is nothing new. I have on my bookshelf a copy of “American Plants for American Gardens” by Edith Roberts and Elsa Rehmann, published in 1929. It speaks of an ever-increasing demand for native plants that “fit into the informal, intimate, seemingly unstudied effects that are sought for in many grounds and gardens today where flowers are luxuriantly intermingled, boundaries are freely planted, trees are irregularly grouped and lawns are sometimes left unclipped.” Roberts was a plant ecologist and Rehmann a landscape architect, a partnership we need to see more often these days.
Perhaps the most significant force at work is a desire to feel closer to nature. We feel compelled to go beyond creating gardens that simply look like nature and are striving to create gardens that also act like nature, gardens that provide suitable habitat for wildlife, that recycle resources and foster biodiversity. We are interested in the marriage of ecology and landscape design.
Growing native shrubs is a decision to be intimately involved with the landscape, for much of their beauty is subtle. Even the commercial successes have elusive qualities that we miss unless we walk into the garden, look closely, stick our noses or focus our eyes in the right place in the right season. For example, you must look closely to notice the bronze freckles spattered on the golden autumn leaves of summersweet clethra, Clethra alnifolia, a native species popular for its sweetly fragrant summer flowers.
Another example of the subtle beauty of native plants is the speckled alder, Alnus incana ssp. rugosa (Zones 2-6), named for the white, warty lenticels on its bark. It can be found growing in colonies along the banks of streams and ponds, in low, wet openings in the woods, in swamps and bogs. And this is where it should be grown in managed landscapes, naturalized in wet areas with willows, nannyberry viburnum (Viburnum lentago) and gray birch (Betula populifolia). While extremely tolerant of flooding, it is intolerant of shade and should be planted in open areas.
Speckled alder is an aggressive colonizing wetland shrub without brilliant spring or summer flowers, without showy fruit or handsome fall foliage. But I love to see this plant in winter, the long, drooping, purple-brown catkins covered with snow. It always brings a smile to see such rich color amid the bleakness of winter, and I never tire of it. Then one early spring day, the snow melted by bright sunlight, the color of the catkins changes to more of a yellow-brown as the first grains of pollen appear.
Winter in Maine would feel incomplete without the catkins of speckled alder, both the showy male catkins and the smaller female catkins that later will become small, persistent, woody cones. Speckled alder is the only common New England native shrub that displays catkins of both sexes on winter twigs.
Alders are important members of wetland communities. Before they turn woody, the female catkins produce tiny winged nuts that are a favorite food of redpolls and other songbirds, waterfowl, small mammals and deer. Alders are nitrogen-fixing plants capable of adding up to 5 grams of nitrogen per square meter of topsoil per year. Their roots anchor the soil and prevent bank erosion.
And they enrich our winter walks.
Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to reesermanley@shead.org. Include name, address and telephone number.
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