There are a lot of ideas floating around these days about what sustainability means in a garden. Several articles in this July issue address the subject; Owen Dell’s new book, offers a guide to designing the sustainable landscape; and our next symposium, Gardening Under Mediterranean Skies VII, will focus on aspects of sustainability.
There is a broad range of situations in which a garden might be created, and a range of solutions for each situation. At one end of the spectrum might be a garden of native plants, grown from locally collected seed sources, planted in native soils at the beginning of the rainy season (autumn in the West). At the other end could be a container garden of moisture-loving plants in the arid climate found in much of the West.
At the one end, only minimal inputs of energy and resources should be necessary to get the native plants established and to allow them to mature in the garden—an obviously sustainable solution. At the other end, constant inputs of water and fertilizer will be necessary to guarantee a healthy growth of the plants. Yet, the solution of a container garden may be the only one available in the particular circumstance; the plants contribute oxygen to the atmosphere, may provide edibles for the table, or nectar and pollen for winged visitors, and will, hopefully, contribute to the visual aesthetics of the setting.
There are countless variations, or gradations, between the two ends of this spectrum of design solutions. Each one of the points on that scale has inherent pros and cons—tradeoffs that may make a particular solution appropriate, and valuable, for a given situation.
A living roof, as one extreme example, requires a good deal of technological stuff, including manufactured materials, to allow it to function properly: protection for the real roof; lightweight materials to contain the soil; systems for irrigating, for removing excess water, and for providing nutrients; monitoring during stressful times (heat of summer, perhaps cold of winter); and access for ongoing maintenance. Yet the tradeoffs can be substantial: increased longevity for the roof; a moderation of interior temperatures; a reduction in the urban heat island effect; additional oxygen for the atmosphere; a reduction in runoff; enhanced aesthetics; habitat for wildlife; and perhaps the preservation of species. All of that more than balances the effort and energy that goes into creating and maintaining a living roof. Alternative roofing solutions offer virtually none of the positive contributions provided by the living roof.
Each of the decisions in designing and maintaining a home garden can be evaluated in much the same way, by analyzing the overall impact of that particular choice of plants, paving materials, irrigation systems, or pruning practices. If we consider each of those decisions against the ultimate impact on our environment, we might begin to make decisions that have the greatest positive overall impact—or at least have the least negative impact.
Sustainability is the theme of the seventh edition of Gardening Under Mediterranean Skies, to be held in Santa Barbara this fall. The first weekend filled so quickly that we have organized a repeat of the program on the following weekend. We hope these weekends will provide inspiration for how we can have a positive impact on our world by making the right decisions in our gardens.
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Readers have been asking about the Laboratory Report, Dr Robert Raabe’s quarterly contribution to the magazine, which has been missing from both April and July issues. Like many octogenarians, Dr Raabe has been dealing with some of the frustrations of an aging body. With the success of his recent cataract surgery, however, he expects to be back at the computer preparing his next Lab Report for the October issue. He extends a huge thank you to all those concerned about his welfare and looks forward to continuing his contributions to the pages of Pacific Horticulture.