Re: Sustainable Landscapes?

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I've been looking forward to a discussion of water and landscapes. Here are some random thoughts.

Graywater is one solution that lets you water your landscape. A huge problem no one addresses is that drinking water is used to flush toilets and do laundry. I read an essay once that suggested drinking water needs to be filtered a lot more than it is, and nonpotable water does not need all that treatment.

From ancient times, a garden was an oasis, so by definition it included a water feature and was lush and produced food. That's what I think about when I think about gardens, so I have trouble calling those arid stonescapes with scratchy plants a garden. Maybe an outdoor room, or (if it's native plants) a habitat.

Michael Reynolds's earthships in the New Mexico desert are fully self-sufficient in energy and water, and they include gardens and sun spaces. So there are ways to have water and lush gardens without piping in water from other places. A fairly recent documentary on his buildings made from mud, aluminum cans, glass bottles, and tires is entitled Garbage Warrior.

It's a matter of scale. Here in northern California, I live in a neighborhood where big houses are surrounded by lush lawns and water-hungry plants. People spend hundreds of dollars a month to keep it green. For the most part, the bigger the yard, the less it's used. And then we have a community garden that accommodates around 150 gardeners on the amount of land used by 2-6 of those big houses.

If you've ever had a food garden, you know how small a space can be incredibly productive. So if you're working within the piped-in-water paradigm, the area around the house can be the food garden oasis, and farther out you can have the habitat garden. That way, the plants are not merely decorative.

Tanya

Sunset zone 17

At 7:47 AM -0700 6/26/09, Ben Wiswall wrote:

Hi All,

I'm hesitant to post this on the list-serve, as I'm afraid I will alienate many people I would rather not. Nonetheless, I've been mulling this topic over for some time, and would appreciate the dialogue.

At an MGS Meeting in San Diego, I heard an early proponent of ecological gardening lecture on sustainable landscaping.  He gave a good test for a garden's sustainability: leave the garden alone for one year, then come back and see how it looks.  Is it alive?  Completely overgrown, or just needing a thorough clean-up?

I haven't tried this on my own garden, but I did see the experiment performed on a conventional southern California garden.  A house in our neighborhood went into bank foreclosure in Autumn 2007: the sprinklers were shut off in November, and I monitored the garden over the following year.  By August, the plants that still looked good in full sun were Brachychiton populneus, Leucophyllum, and Myoporum parvifolium.  Sheltered by the house and garden walls, Ficus nitida, Duranta, and Pandorea pandorana looked presentable.  Roses, Nandina, Pittosporum, Phormium, and Hemerocallis were all severely stressed by late summer, but revived with cooler Fall weather.  A young Jacaranda, a Liquidambar, the Trachelospermum, and the lawn were all dead.

(The house has since been sold, the lawn replaced and the sprinklers are back on.)

This got me thinking: what would happen to all of southern California if we all ignored our gardens for a year?

I suspect the result would be a brittle, tinder-dry urban forest; left alone, it would be fuel for devastating fires.

We in southern California depend on water transported long distances.

I once consulted a contractor about building a cistern, and he gave me an informal quote of well over $20,000 US to build an underground cistern capable of holding a winter's worth of rain from our roof. This water would provide for less than five weeks of indoor water, OR about 15 cm PER YEAR in the garden.  And we would still require distant water.

So what is sustainable?  If sustainable means self-sufficient, we aren't: southern California cannot support its nearly 20 million inhabitants without importing most of its water.

Of the water used in the state, 77% goes to agriculture, 3% goes to public works, 10% is used industry and commerce, and 10% is used in residences.  Of that 10%, about half, or 5% of the total, is used in home landscaping.

Water, like all natural resources, should be used prudently, with consideration both for protecting rare species and for the larger sphere of life we all inhabit.  It is likely that water will become scarcer in the near future.  Still, if every homeowner in the state were to replace their lawns (and bananas, avocadoes, azaleas and impatiens) with myoporum or gazania, we might save 2% of all the water used in the state.  I don't much care for lawns, but should I care so much for saving so little water?  Especially as a 10% reduction in agricultural water use would yield a far greater savings than ALL the water currently used in residential gardens.

In regions on the cooler, moister side of the mediterranean spectrum, dry gardening is more popular: at the hotter, drier end of the spectrum gardens tend to be a celebration of water.  Living at the drier end of the spectrum, I try to like dry gardens, but find they leave me thirsty and unsatisfied beneath the blazing sun of inland southern California.  I would also feel unsafe against wildfires in a garden that wasn't irrigated at least 3 times a month.

So what to do?  I have a need for a certain amount of moisture in a garden, enough to make me comfortable in the heat of summer and to feel safer against wildfires, yet I don't want to waste a precious resource.  But even a semi-dry garden requires far more water than can be provided for locally.

Any thoughts?

Ben Armentrout-Wiswall

Simi Valley, Inland Ventura County, Southern California

PS  It can be a nuisance to get there, but I have a corollary photo set on flickr.com titled Notes on the Urban Forest.  The photos are all captioned, but it works best as a slide show: