Shut Up and Dig

Xeriscaping – Just a Myth After All?

A recent commenter here alerted me to Linda Chalker-Scott, a Ph.D. horticulture prof at Washington State U., director of their Master Gardener Program, and the primary hort authority behind Master Gardener Magazine.  She’s known for her articles debunking Horticultural Myths, and who can resist a good debunking? 

So like any long-time gardener, I breeze through the myth articles, feeling smug beCactus_1cause I know better than to fall for them myself.  And then she lays this one on me:  "The use of drought-tolerant plants reduces water consumption," which she calls the Myth of Xeriscaping.  WTF?

Here’s her point as best I understand it.   Yes, drought-tolerant plants (like cacti and mesquites) can survive with less water, but in drought situations they drop leaves and slow their growth and thus are "less aesthetically pleasing".  As a result, homeowners, even if they understand the importance of water conservation, crank up the irrigation so the plants will look better and wind up using more water than their neighbors with "traditional landscapes."  So ironically, the more environmentally concerned homeowners end up using the most water.  Linda’s prescription:  We need to "develop a new philosophy," in which we accept the horrors of leaf shedding and reduced growth.   OR, I’d suggest, ask for plants that still do well under drought conditions.  Is that asking too much?

And there may be an actual university-sponsored study in Arizona that showed increased watering by homeowners of their xeriscape gardens but frankly, IT MAKES NO SENSE.  Maybe the study subjects were check-writers, not gardeners.  Any other ideas?

But the blame doesn’t just lie with profligate homeowners; it’s also the fault of those damn drought-tolerant plants.  Research has shown that mesquites use more water than oaks under
optimal conditions.  After all, it’s their very ability to take up and store water, camel-like, what makes them drought-tolerant.  But if they take up water when it’s plentiful, what harm is done? 

So let’s assume for the sake of argument that Linda’s point is well taken (because hey, she’s got the credentials).  If drought-tolerant plants AREN’T best for water conservation, what plants are??  What about the non-succulent drought-tolerant plants, like daylilies, salvias, nandina or the rugosa rose?  And is her point that we should avoid drought-tolerant plants or just get used to them looking crappy?  Linda, please clarify.

Photo taken Thanksgiving of 2005 in Tucson, AZ.

Posted by on November 17, 2006 at 4:38 am, in the category Shut Up and Dig.
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12 Responses to “Xeriscaping – Just a Myth After All?”

  1. Amy Stewart says:

    I think we really should get used to them looking crappy. Plants are a part of the natural world, and they go through life cycles. One of the things I love about the world of Piet Oudolf (who really deserves a good rave one of these days) is that he loves plants that look good when they’re dead–or, more properly–dormant.

    If it’s hot and dry and thirsty, your plants will look hot and dry and thirsty. Big deal.

    I think xeriscapers (or really, all of us) need to do two things:

    First, garden in zones. If you want some pretty flowers around your patio or your hot tub, or a vegetable bed with a few tomatoes, fine. You’ve got a little area that does need regular water. Another zone might need some water once or twice a month, and if your property is big enough, there’s probably a zone that gets no extra water, period.

    Second thing: beneficial microbes that actually help extend the root system and allow plants better access to what little water there is. High Country Gardens has gotten into this in a big way. You would not believe how good their demonstration gardens looked at the end of a long drought. (They sell the stuff–it’s called Earth Magic–but you can find something similar locally, too.)

    But it doesn’t surprise me that human behavior gets in the way of the ideal dry garden! It’s like the thing about mutual funds–they perform however they perform, but individual investors never do as well as the fund overall, because we tend to buy high, sell low, and make other silly mistakes!

  2. Gloria says:

    Amy is so right. There is beauty in the dormant season of plant life and Piet Oudolf is a genius at bringing this beauty to public attention.
    His plant design work at the Lurie garden in Millennium Park, Chicago is a work of art.
    I am a volunteer worker there with the Master Gardener program and have been taking pictures through the seasons. Here is a link to my favorite winter shot from last year.
    http://s101.photobucket.com/albums/m56/entwife_2006/?action=view&current=Lurie3-2-06.jpg

    While the spring, early summer and fall draw the most comments from visitors there is a growing group of enthusiasts for the winter.

    Over half of the planting is native to North America. The others are plants that fit the climate and purpose of the garden.

  3. JLB says:

    I second and third the notion to just “get used to things looking crappy from time to time,” or perhaps better put: learn to appreciate the aesthetics of seasonality.

    I don’t wish to cast doubt on Linda’s credentials, but I was a little curious about the uncited, “study in Arizona several years ago”. If she is using this as the basis of her conclusions that drought-tolerant species truly consume more water than other plants in the hands of well-intentioned but un-informed gardeners, I’d be interested in some cold numbers just for kicks.

    While not specific to xeriscaping, I see the same resistance to seasonality in the way some people care for their lawns. It perpetually disturbs me to find that in the peak of summer, when the heat is high and the water availability is low, that some choose to crank up the watering and fertilizing of their lawn, leaving them unseasonably green.

    Linda emphasizes “a different philosophy of landscape aesthetics”, and I think that could be a beneficial shift in mind-set for many gardeners.

  4. There are far too many interacting factors in a living ecosystem to make a sweeping statement that xeriscapes use more water. Her Arizona study is one example in one part of the nation using one type type of plant palette for comparison and possibly in a gated community where “aesthetics” matter and water bills don’t. So I would be a bit leary of such a study without knowing all the particulars of the sample group.

    Having said that, it is no surprise to me that when you throw in the human factor in the living ecosystem a study could find xeriscapes use more water.

    Far too many people think water is the solution to all plant problems. Just as many who use landscaping services absolutely refuse to take any responsibility for their irrigation systems and water use.

    http://tropicalembellishments.blogspot.com/2006/03/puddles.html

    Not to diss my own profession but it isn’t easy to manage water use for twenty properties and who is going to drive around town and shut systems off when it rains because the home owners are too lazy to turn a knob. It is easier to just let the water run sometimes.

    Imagine that when the power goes out the home owner does nothing and waits for the maid to come to reset all the clocks, VCR, DVD, computer and other time sensitive appliances and never shuts a light off and leaves everything on all the time. Then they get pissy when the electric bill comes.

  5. max says:

    Beware of people on the internet who claim to “debunk” anything.

  6. “We need to “develop a new philosophy,” in which we accept the horrors of leaf shedding and reduced growth.”

    Except, we won’t. It is nice to talk about what we should do. I’d rather talk about things we are likely to get people to do. In order for anyone to change in any way – attitudes, behaviors, perceptions – TWO THINGS have to happen. First, we need to be ABLE to change. Second, we need to be WILLING.

    No doubt we are able. But willing? Growing pretty flowers in non-native environments for non-natural results is an ancient part of the human condition.

    The real issues here are not that gardeners are using too much water. Gardeners – even those who do bad things – are the good guys in the big picture. The problem is we are polluting our air, water and soil at incredible rates so that which is left over is more precious.

    The damned planet is covered wirh water. Rather than ask the world to stare at wilted cactus, lets find a way to take care of iour WATER CYCLE so we can use a miniscule amount to water our peonies.

    That’s my two cents. I’ll step down now. (Good post!)

  7. Reading Dirt says:

    Everyone is into debunking something these days. I think the real problem here is when people are sold “drought tolerant” plants and the seller isn’t specific about what “tolerance” means. Buyers assume it means the plants keep looking great all summer. But it could mean, “These things fall over and look dead in the heat of the summer, then bounce back all by themselves at first rain.” So if you’re going to xeriscape and want stuff to look good, you might seek out the former and bypass the latter — if you know enough about the plants to tell the difference.

    Xeriscaping is a lot more than poking “drought tolerant” plants into the ground and standing back. You have to pick the right plant for the spot and know what to expect of it. Just like any other kind of gardening.

  8. Kim says:

    All interesting comments… I have nothing to add except to point out that Piet Oudolf is by far not the only gardening guru who advocates enjoying the natural decline and decay of some plants. I own and enjoy Noel Kingsbury’s “Seedheads in the Garden,” and have also noticed some use of seedheads and other dead material in the gardens at Great Dixter via Christopher Lloyd’s book on succession planting.

  9. Richard Boyd says:

    LCS is a star!

    I’ve no idea what : Christopher C in Hawaii means by his comments, could be the beer I suppose

  10. Richard, drink two cups of coffee or a spot of tea and read it again in the morning while thinking tangential thoughts. There is an under current of coherence you may be able to pick up.

  11. firefly says:

    I spent some time with the “myths” series of fact sheets (no worries about cedar bark mulch inhibiting plant growth, yay!) and took a look at Chalker-Scott’s CV, which is certainly very impressive, but I agree the lack of references in most of these publications is a little odd.

    I’m sure the reason is that she is writing for a general audience who are perceived to not want to be bothered checking out individual studies, but still, it wouldn’t kill anybody to have a few citations at the end of an article, mainly because it’s entirely possible that there are contradictory studies out there as well.

    As for ‘xeriscaping,’ I’m a bit bemused by the blanket recommendation for ‘drought-tolerant’ plants. The climate here in coastal Maine would surely kill a cactus dead as a doornail: wet springs and autumns, cold winters often with several feet of snow, and July and August the only months in which rain is scarce. I have read ‘expert opinions’ stating that it is likely that perennials which fail do so in winter because their feet get wet and they can’t tolerate it (no URL, sorry). Frankly, I wonder how sedum, which is sometimes used here in foundation plantings, hangs on through some of the rainfall we get.

    To me it seems much more sensible to find plants (native or not) that can accommodate to seasonal patterns rather than just ‘tolerate drought’ so the gardener doesn’t have to water.

  12. chuck b. says:

    Most cactus love water. They will grow and grow and grow with regular watering. They just don’t like to soak in it. My granddad planted Opuntia because the deer don’t bother them, and he watered them, and they’re huuuuge.

    Irrelevant, I know.

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