By Michael Nerrie
'Home & Garden' magazine of the Keene Sentinel newspaper
April 8, 2016
Old School Landscaping
Thirty years ago, when my wife Kathy and I began developing our Walpole property we would later name Distant Hill Gardens, our very first purchase of plants was the New Hampshire State Nursery ‘Song Bird Package’. We were excited when the bare-root seedlings arrived that spring and we quickly planted them with high hopes for their future growth. Little did we know that years later the multiflora rose, autumn olive, and oriental bittersweet the State Nursery sold us in 1988 would all be placed on the New Hampshire list of non-native invasive plants!
In 1990 we began working on the ornamental gardens at Distant Hill in earnest. In those early gardening years our winters were spent thumbing through nursery catalogs looking for trees, shrubs, vines, groundcovers, and perennials that offered the showiest flowers, the longest bloom time, the best fall color, and all with the promise of little or no insect damage. Looks were everything!
We were following the accepted definition for landscaping at the time: to improve the aesthetics of a property by including visually beautiful, unblemished plants within the landscape. The relationship of the plants in the landscape to the overall ecosystem and its biodiversity was rarely discussed.
Looking back on it now, it is hard to believe that the terms “invasive”, “native”, and “biodiversity” were not in the landscaping lexicon of the time. As late as 1998, the year I completed the New Hampshire Cooperative Extension Master Gardener program, there was still no mention of the advantages of landscaping with natives plants, no discussion of invasive plants, nor any talk about the importance of biodiversity.
Thankfully, over the past decade the focus of landscaping solely on aesthetic criteria has been slowly changing. We are beginning to realize that the plants we include in our gardens can meet our need for a visually beautiful landscape and still play an important role in improving biological diversity.
This new shift in thinking often recommends the planting of only native plants in our gardens. Studies have show that native plants tend to support more caterpillar and insect species and therefore will draw more wildlife and be more beneficial to the ecosystem in general than alien plants. I feel, however, there is a problem with the vague and varied definitions of “native” used by the many voices in the discussion. Some gardeners are purists and follow their definition of “native” to the letter, not taking in to account a non-native plant’s attributes and ability to add to biological diversity and a functioning habitat for wildlife.
Doug Tallamay in his landmark book ‘Bringing Nature Home’ discusses using a functional definition of "native" as opposed to a chronological or geographic definition. Instead of thinking of a native plant as one that grew here prior to a certain date, such as before European colonization, we should think of a native plant as one that has evolved in a location long enough to be able to establish a specialized relationships with the ecosystem. It doesn’t really matters how long a plant has been present. What matters is that a plant is a functioning part of the ecosystem as a whole. As Tallamay states: “Let nature define nativity”.
A good example of this is the common or purple lilac (Syringa vulgaris) a flowering shrub native to the Balkans in Eastern Europe and brought here by the colonists. Common lilacs are alien plants if you are using either the chronological or geographic definitions for a non-native. However, lilacs are known to support 40 species of native caterpillars and are more valuable in that regard than many true native plants. I can’t imagine our New England landscape without our New Hampshire State flower, the purple lilac, and neither can the caterpillars and butterflies that now depend on this non-native alien!
Gardening With a Purpose
In designing our landscape at Distant Hill Gardens, we are still concerned with providing a diversity of visual form, texture, and color to the garden for the human eye, but we believe that we as gardeners can play an important role in sustaining local biological diversity by providing a diversity of plants, both natives and well-vetted non-natives. Although we have just begun to scratch the surface in our understanding of the interactions between our gardens and the natural world in which we live, what is becoming clear is that the greater the diversity of well-chosen plants we include in our landscapes the greater the overall biological diversity.
For too long we have considered our landscapes to be visually beautiful sanctuaries, separate from nature. It's time to step back and realize the larger role our gardens play in sustaining the diversity of life that is essential for a healthy and beautiful world.
April 8, 2016