What is a weed? I have heard it said that there are sixty definitions. For me, a weed is a plant out of place. ÜDonald Culross Peattie (1896-1964), botanist and author

For some, gardens are an extension of their physical property, a natural space to compliment the home. For others, gardens are an extension of their psyche, an expansion of ideas, a place to let the mind wander and a place to establish a tangible connection to the earth. For the latter, sustainable landscaping makes sense because it involves practices and analysis more closely tied to the ecosystem where the garden grows.

What exactly is a sustainable garden? Is it filled with native Hawaiian plants? Does it conserve water and use recycled materials? Are the plants useful in some way, whether for food, medicine or material? Are the bugs out of control? The answer is not so black and white. As Leland Miyano, landscape designer, sculptor and naturalist, would tell you, it's a continual work in progressÜa controlled ecological experiment.

Gardens are site specific and gardener specific, so no two are alike. But the principles behind sustainable gardening, though many and diverse, can offer a rewarding venture for the conscious gardener as well as the environment, no matter what the combination of conditions and practices. Taking advantage of the local ecology in your specific area, like temperature and rainfall, and using them to your advantage is simply the key.

Leland saunters down one of the many dry-laid stone paths that wind through his one-acre "backyard" garden. Some of the stones are large, flat and rectangular, stones he retrieved from a swimming pool excavation that were headed for the landfill. Artfully juxtaposing the angular stones are round and smooth cobblestones, which were found in the farmers' fields near his home. Situated in the Ka'alaia Valley on the windward side of O'ahu, the private botanical retreat was never meant to be a public place, but his efforts to grow natives, be water wise and use recycled materials have transformed the garden into a living demonstration in sustainable gardening techniques and an educational arena. And Leland is embracing his role as ecological designer and educator.

"I would call myself a naturalist. I love all of natural history, not just the plants, but the animals, everything that's impacting this place," says Miyano, as he wanders through his garden complete with canopy, understory and groundcover. He pulls weeds and dead leaves as he walks and throws them into strategic piles along the pathway. "That's as opposed to a specialist. A specialist tends to look at one thing and they're not looking at the ecology of something. I'm always looking for more naturalists in this world because I think that too many people are specialists.

"You have to be a naturalist or generalist thinker in order to see the big picture and to see this thing as a holistic system that somehow works together. That's why I keep my options open so I can understand what I'm seeing in front of me. Then I analyze that and make my decisions and that's why I'm trying not to make too many rules for myself here because this is a grand experiment. It's not necessarily a designed garden, but the plants are driving the design, or the ecology is driving the design. And yet it still has to be a livable and usable space."

Leland sets the bar by defining his sustainable garden with loose guidelines while working within the ecology of the valley: low maintenance, using natives when possible, being water wise and growing plants with purpose or utility. What started out more than 25 years ago as a field with several invasive trees has transformed over the decades into a lush garden that is self-sustaining and productive. "I don't have an irrigation system. I rely on the rain. I don't want this garden to be dependant on me," says Miyano.

To accomplish this, Leland is growing plants that thrive in the particular microclimate in which he lives. The valley receives more than 70 inches of rain per year and Leland has designed the dry-laid stone pathways to move water through the garden as it percolates down through the stone.

Following several of these paths to the back of the garden, Leland surveys the young starts growing in the nursery. Set on brick recovered from a contractor's dump run, hundreds of species of exotic and native plants spread their roots in small growing containers resting on stainless steel refrigeration racks from WWII and recycled-plastic benches, which he prefers to reclaimed lumber because they are termite resistant. Old restaurant stainless steel sinks and racks hold a potpourri of gardening supplies.

He points out one of his mulch piles on the other side of the path, a 6-foot high, 12-foot long pile of organic debris. He started this pile a year ago and plans to harvest in about six months, digging out bucket loads from the bottom of the pile. As part of his penchant for low maintenance, he doesn't turn his piles, allowing the breakdown process to run its natural course. He refers to this pile as the "small" compost pile.

Leland explains that while growing his garden of experimentation and design, if plants don't do well on their own, they tend to get shuffled out of the deck, his method coming from years of species analysis. "The one thing that I do not want in here are invasive plants. Some plants may not be invasive for a long time and then they start manifesting characteristics that are too much for me to handle and then they are edited out."

For the humble naturalist, native plants are important in the garden, but not the end-all be-all for a sustainable garden. According to Leland, the natural ecology of pre-contact Hawai'i is so altered, that a mix of exotics and natives works best for him. "I have a lot of native plants planted in and amongst things. I try to grow non-invasive ground covers that are easily gotten rid of if I have to take them out," says Miyano, "just waiting for the natives to grow, because a lot of the native species are a little slower to grow. As the native plants get a little larger and more vigorous, I take out the other ground covers. I grow herbs as ground covers too. I'm trying to introduce more of the edible component-Italian parsley, peppers, basil-but it's all part of the landscape."

In addition to the ongoing work designing and planting in the garden, Leland toys around with hybridizing ti to develop disease resistant varieties of the plant so people can enjoy trouble-free ornamentals for their homes without having to spray chemical pesticides. He also is working to develop disease resistant 'o-hi'a lehua, which is taking a big hit on O'ahu from 'o-hi'a rust.

"The whole garden is attempting to be sustainable," continues Miyano. "I say attempting because it's a process. I make mistakes, everyone makes mistakes, but if you observe and trust your own eyes you can see what works and what doesn't. And things may change, for example I have a lot of plants that I don't know exactly what the growth rate of the plant will be, but I'm not trying to control the growth of that plant, I'm trying to see what it will do in this ecology."

To answer our question about what components are required for a sustainable garden, the one thing that holds constant is to make sure that no plant is out of place.