April 2008

Developers are “greening” their landscapes... finally

The lovely landscapes at Brookside garden feature the environmentally beneficial use of trees, but also the challenges of thirsty turf grass. Photo: Julie Wiatt

LEED ratings for eco-friendliness in new buildings are all the rage in the construction world. The acronym stands for Leadership in Energy and Environmental Design and developers are suddenly scrambling to get them because they add so much to the selling price of both commercial and residential buildings. Some government contracts are even requiring them.

But the next big thing is that LEED standards will soon include the “greening” of landscapes, thanks to the work of American Society of Landscape Architects, the Lady Bird Johnson Wildflower Center and the U.S. Botanic Garden. They’ve teamed up to form the Sustainable Sites Initiative and their experts (including Behnkes nurseryman John Peter Thompson) are working hard to establish standards for things like percentage of green space, erosion prevention, waste management, wildlife habitat and - get this - even human health, cognitive function and social dynamics. This holistic approach is rarely seen in discussions of “sustainable gardening,” so I was pleasantly surprised to see these folks get it right.

The result of all this work will be incentives for developers to discontinue such destructive practices as scraping away the topsoil, causing erosion during the construction process, and using such resource-intensive features as manicured lawns and beds of annuals. So the greening of landscapes won’t depend solely on convincing individual homeowners to get with it; the market forces will incentivize the developers to do it for them.

Why all the attention to landscapes?

• Vegetation captures and stores carbon dioxide, thus removing it from the atmosphere.

• Urban trees in the U.S. capture as much as 25 million tons of carbon each year.

• Trees also reduce the urban heat island effect and provide windbreaks. Landscapes that include a mix of native and ecologically appropriate non-native plants increase biodiversity and provide for wildlife.

• According to a U.S. government report, homeowners use about 10 times as much chemical pesticide per acre on their lawns as farmers use on their crops, which is saying a lot. All those pesticides — just for lawn?

• Turf grasses are the single largest irrigated crop in the U.S. in terms of surface area, covering an area the size of Mississippi. Again, that’s a whole lot of water being used for lawn.

• Up to 18 percent of the material in landfills is yard waste, most of which isn’t really waste at all but plant material that could have gone to create compost.

• Research has shown that just looking at plants is good for us. Nursing homes see decreased numbers of “behavior incidents” after plants are incorporated into the grounds. Trees and other plants have been credited in other studies with reduced crime, stronger ties among neighbors, more frequent use of common neighborhood spaces and a greater sense of safety.

Steve Windhager of the Johnson Wildflower Center explained all this recently at a one-day symposium at Brookside Gardens about the Sustainable Sites Initiative. And he revealed the almost sudden urgency among developers to improve their landscaping practices: because there’s a race to achieve carbon neutral development and it cannot be done without using landscapes effectively. They need the carbon-sequestering and runoff-reducing work of plants to get there.

Waste Not!

Next up on the Brookside program was Jean Schwab of the U.S. EPA talking about waste, a surprisingly compelling subject. Seriously, her trash show-and-tell was positively entertaining, with such highlights as a view of Mt. Trashmore, a large trash mound in Virginia Beach. Apparently when you can’t dig down, you just pile up. Pity the folks who live within nose-shot of these unholy mounds.

But remember all that organic matter that’s filling up our landfills? Schwab is passionate about the benefits of composting all that good stuff instead of trashing it. She explained that organic matter in soils determines their ability to hold water and the ability of plants to access nutrients in the soil. And while mixed borders need about 10 percent organic matter to do their best and even turfgrass needs 5 to 6 percent, soils in most new developments contain less than 1 percent organic matter. (So will new tract houses soon be equipped with compost bins? It’s not unimaginable.) Schwab also mentioned that sprinkler systems increase water bills by about 50 percent — talk about waste! — most of it going to lawn.

Invasive plant report

Last on the agenda, Valerie Vartanian from the Nature Conservancy gave a rousing rant against invasive plants - and Voice readers see enough aggressive, tree-strangling vines around town to need no convincing that this is a huge problem. There is some good news on the human front, though, like the fact that some retailers are removing invasives from their stores, even one bigbox in the Midwest.

Vartanian applauded the Sustainable Site Initiative’s emphasis on native or regional appropriate plants that are not just well behaved but also low-care and sometimes even fully sustainable (meaning no-care). But unlike some groups involved in invasive plant eradication, the Nature Conservancy doesn’t rant against the growing of nonnative plants and Vartanian even declared her love for them, exclaiming, “I love exotic plants, especially the Bird of Paradise!” She assured us that the vast majority of nonnatives are not a problem, as seen in Hawaii where there are over 13,000 nonnative species but only about 1 percent are invasive.

So rather than trying to ban nonnative plants, she applauds the growing consensus that the solution is to assess plants for their potential to be “weeds”, something that the USDA has finally started doing. And some states are imposing quarantines pending testing, while others are buying up stocks of invasive plants. Even mega-grower Monrovia has gotten into the act, developing standards of conduct for growers and sellers of plants. Notice how the business world is finally figuring out that if their practices aren’t environmentally responsible, they won’t be in business for long? That’s how mainstream “green” is. Finally.

Master Gardener Susan Harris is a gardening coach and writer. Visit her blogs at TheGardeningCoach.com, Sustainable-Gardening.com, and GardenRant.com.

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