“…One question for your travels. As you see mandala gardens, herb spirals, and other popular permaculture style gardens, I would be interested in your views on how effective they are from a functional perspective…. I visited one garden last summer whose owner felt that the herb spiral didn’t really work.”
This is an excellent point, and illustrates the old adage that one size does not fit all, even in permaculture. By definition, permaculture is a “design solutions framework” and if one strategy, structure, or implement is not working for an individual site, then perhaps an alternate approach needs to be considered. An herb spiral, while extremely popular in permaculture gardens, is not a requirement in permaculture, and an extremely effective permaculture garden can be created without one. Just as I suspect an extremely ineffective permaculture garden can be created despite incorporating a myriad of popular permaculture elements. Myopic focus on a particular element within a system in the absence of adequate attention to the need for the element and how it works in tandem with the entire system, idiosyncrasies and all, risks compromising the system’s overall functioning integrity. I would want to ask, “What wasn’t working about the herb spiral?” and “What was the purpose of the herb spiral?” and suspect the failure of the herb spiral would lie somewhere astraddle of the answers to these questions.
That being said, I am convinced there is a serious need for research in the field of permaculture. And lots of it. Because science is very reductionist by nature, it is extremely difficult to adequately assess efficacy of permaculture as a whole within an experimental design. Despite these barriers, it will be essential to consider permaculture practices through quantitative research. Companion planting is one such practice widely used in both permaculture and horticulture, yet few quantitative studies have been produced backing its efficacy.
I will go forward with a mind to ask about function and efficacy of the permaculture practitioners I meet, but I invite all readers to reply or send me an email with your thoughts and experiences on specific permaculture practices, as well as any studies you are aware of that provide support for permaculture practices.