Re: Sustainable Landscapes?

I teach "Sustainable Landscaping/Garden" at three of the colleges around here.
 
I always start by saying that everyone has their own definition of "sustainability".  Adding to that, I state that everyone has their own degree of "acceptable" sustainability.
 
I'm somewhat flexible and I do my best to not "dictate" that everyone MUST reduce water use in the garden by 99% by x date.
 
But I do my best to make it clear that a "sustainable" landscape/garden is NOT a garden of rocks, gravel, sand, cactus, and spikey things (as once generalized when gardeners heard the word "xeriscape").  Nor is it something that looks like a "tinder-dry urban forest" if neglected.
 
Mother Nature is our ideal of "sustainable".  But for those of you who've been watching her over the last few years, through 2 or 3 really dry winters, she's actually kind of messy about it, maybe even unattractive.
 
We don't live in caves any more and our paradise is the garden we create, to be sure.  My challenge is to show my students that their paradise actually can look pretty darn good while reducing water use by a significant amount.
 
As another Med Forum member already posted, there are plenty of gorgeous gardens around that are, indeed, sustainable to the point that virtually no water is used to sustain them.  I've designed at least 2 landscapes in the "tropical" style, using Mediterranean clime natives (primarily California natives).  These landscapes are green, lush and colorful.  Contrary to everyone's stereotypic idea of a water-conservation garden.
 
I even give my students pages of lists of edible plants (primarily sustainable fruits and nuts) that will survive on minimal to zero water.
 
Our population is expanding and potable water is not.  2% is a lot.  I'm not sure what I can do about agricultural water use.  I might be able to do something about industry use; I'll have to figure that out.  But I'm positive, though, that I can and should do something about home landscape water use.
 
Joe


Joe Seals
Horticultural Consultant
Pismo Beach, California
Home/Office: 805-295-6039

--- On Fri, 6/26/09, Ben Wiswall <benwiswall@pacbell.net> wrote:

From: Ben Wiswall <benwiswall@pacbell.net>
Subject: Sustainable Landscapes?
To: "medit plants forum" <medit-plants@ucdavis.edu>
Date: Friday, June 26, 2009, 2:47 PM

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:


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