Monday, June 14, 2010

The End of Groundcovers

If I could banish one word from the English language, it would be "groundcover."  The era of the groundcover must end.  While this age of American landscape design has its roots in the Victorian garden, it has been the dominant landscape ethos since the post WWII housing boom.  The primary idea of this era is that non-lawn planting beds need to be covered in a low maintenance, evergreen groundcovers such as English ivy, periwinkle, or pachysandra.  The results of this philosophy on our landscapes are nothing short of catastrophic: millions of acres of meadow and forest have been decimated by these invasives, and we've forsaken the spiritually enriching act of gardening for the environmentally impoverishing act of landscaping.

The Rise of the Groundcover
It's easy to understand how groundcovers became so popular.  As American suburbs sprawled away from city centers, individual homeowners quickly became absorbed in the enormous labor of maintaining huge expanses of lawn.  With so much lawn to maintain, the rest of the yard needed to be relatively maintenance free.  Planting beds were established where lawn wouldn't grow--typically in the shady areas under trees or at the edge of the lot.  How to fill these leftover beds became a problem.  Next to a manicured lawn, bare earth or mulch looks empty and unfinished, but filling these large areas with plants could be expensive. 

The groundcover became the magic cure.  Tolerant of sun or shade, wet or dry, these low, creeping plants could be sparsely planted in a bed and left alone.  Within a year or two, the bed was covered in lush carpet of glossy green ivy, the bright blue flowers of periwinkle, or the happy white spires of pachysandra. When maintained, the long flowing curves of planting beds created sinuous lines against the lawn, a declaration of the well-tended yard.

But the problem was that these yards were inevitably not well-tended.  The very quality that initially drew homeowners and landscapers to these plants--their ability to spread--became the beginning of an aesthetic and ecological disaster. 

Ecological Disaster
The honeymoon period (two or three years after the installation) yielded to the invasive period, and homeowners quickly realized that these low maintenance darlings actually required maintenance--lots of maintenance.  The plants began to move and destroy: the ivies grew up trees and down slopes; pachysandra crept into a wet area and down stream channels; periwinkle moved across slopes choking all other vegetation in its path.  Not even structures were safe.  The clinging roots of ivies invaded mortar, the muscular branching of wisteria damaged buildings, and the thick impenetrable roots of periwinkle altered the hydrology of yards. [Image to left shows Vinca major, periwinkle, smothering a forest floor].

Often in suburban neighborhoods, the developer backs lots right up against undevelopable land like forested streams or adjacent woodlots.  The groundcovers, unaware of property lines, spread into forests, streams, and meadows.  Vines climb into the canopy, covering leaves and blocking photosynthesis.  The additional weight of the vines often break branches and canopies particularly during snow.  The understory invasives smother the ground-plane, preventing native plants from seeding and regenerating the canopy.  Ecologists call the zones dominated by invasive groundcovers "ecological dead zones." [Image on right shows English ivy decimating forest floor and smothering trees.]

The U.S. Forest Service now estimates that invasive plants like groundcovers strangle 3.6 million acres of national forests, an area the size of Connecticut.  And that's just national forests.  Invasive plants are thought to cover 133 million acres of federal, state, or private land, an area the size of California and New York combined.  Each year invasives march across 1.7 million acres, almost double the size of Delaware. 

An Alternative Concept
The concept behind groundcovers is as pernicious as the plants themselves.  It is based on the mythology of the quick and easy, low maintenance yard.  Groundcovers signal a disconnect between the owner and the land, a message saying "I don't want to deal with you".  The professionals who use these plants, both designers and contractors alike, automatically assume the lowest possible expectations for that piece of land.  Groundcovers are chosen based on the assumption that the area will be ignored, abused, or abandoned. 

Groundcovers represent a failure of the imagination.  Americans understand trees, shrubs, and groundcovers, but beyond these categories, we're pretty much lost.  We lack England's rich garden history and thus fail to understand how to use herbaceous plants like perennials, grasses, annuals, or vines to enrich our planting beds.  Native plant enthusiasts have long recommended native alternatives to invasive groundcovers, but their suggestions typically replace one type of plant with a less invasive counterpart (a vine for a vine, a creeper for a creeper).  What these lists fail to do is to challenge the aesthetic that prompts the homeowner to use a groundcover in the first place. 

The alternative to groundcovers is not slightly less invasive groundcovers, but planting beds filled with native biomass.  We need to re-imagine our beds filled with a rich tapestry of perennials, grasses, shrubs, and low trees.  While our unfamiliarity with these materials make them intimidating, we should rely on the toughest and most resilient native perennials and grasses to fill our borders.  The demand for evergreen should be replaced with plants that provide winter interest: dried grasses, seed heads, and structural deciduous shrubs.  We should transform our ecological dead zones into ecological hotspots by creating connected areas of native biomass.  When we do this, we invite pollinators and birds back into our landscapes. 

[Native biomass: Goldenrod and Echinacea fill a planting bed.  These plants are low maintenance, provide nectar for birds and butterflies, and beautiful as they change through the seasons.]

A Model Project

Ten Eyck Landscape Architects in Phoenix recently completed an award winning project for a labratory building for the University of Arizona.  The landscape around the building functions both as an outdoor classroom and a high performing native landscape.  The project harvests water and provides and interface between students and nature.  The former grayfield is now a thriving habitat for birds such as the roadrunner and hawks searching for ground mammals.  The ASLA awards jury said of the project, "This project shows us everything that we should find in a university landscape.  Not a blurred interpretation of "native" but rather a commitment to accuracy." 

[Students enjoy a break at an outdoor classroom surrounded by vegetation native to the Upland Sonoran.  Photo by Bill Timmerman.]

[The pond is home for endangered fish and is listed by the U.S. Fish and Wildlife Service as a "Safe Harbor" urban site.]

And I'm including one additional image to show how native grasses can be used as a groundcover alternative.  This photo taken at Chanticleer Garden in Pensylvania by Rick Darke. 

[Native grasses such as Prairie Dropseed, Sporobolus heterolepsis, make an ideal alternative to invasive groundcovers.  Photo by Rick Darke.]


  1. What a great blog, Thomas.
    Please consider continuing this discussion by suggesting alternative plants to ground cover that can be used specifically in dry shaded areas where little else will grow.

  2. I have a large shady area in my backyard that has been covered with English Ivy and Vinca for over 20 years. No, I didn't plant it! I've only lived there for 7 years. I have another area that was covered in Wisteria - more invasive than the Vinca and Ivy in my neighborhood. We've managed to get pull out most of the Wisteria. Of course, it keeps coming back and we keep pulling it out. Now what to do about the Vinca and Ivy? We keep it off the trees and out of the neighbors yards but we haven't gotten rid of it. What's a good alternative to shade under large oaks? We do have azaleas and rhododendron and have added hosta.

  3. Allan and Ginny,

    I'll follow up with a blog that deals with alternatives to groundcovers in dry shade. And removing invasives once you have them. Thanks for the feedback . . . those are great points!


  4. Thank you for this post! It makes me even more determined to remove vinca from my garden.Very interesting statistics and history. Great material!

  5. thank you - a most thought provoking post. My only question is what do you plant in shade, dry shade at that. Ivy is naturalised in our woodlands and growing up trees does little or no damage but provides habitats for wildlife. Vinca major is a bit of a bore but the smaller varieties are easier to contain. I agree to an extent about native planting but what constitues a native? Here in the UK we have imported plants from across the world into our gardens for centuries. A current garden trend now is to have American prairie style planting!
    Long winded - Laura

  6. Hi Thomas,
    Couldn't agree more. I do have a small Vinca patch planted long ago, but it is ruthlessly contained and diminished as natives flourish.

    I look forward to reading your thoughts on native substitutes. I'm trying a few new fairly rare native plants, but it will be a couple of years before I'm ready to report back.

    U. of Arizona is where Dr. Michael Rosenzweig, who wrote Win Win Ecology, teaches. Your featured project matches his philosophy through and through.

  7. Oh, the hours I've spent ripping out vinca. I swear, I've come to hate the smell of this plant. And it's the home to untold numbers of snail orgies.

    The vinca in question is in a tiny urban garden that I transformed from trash filled lot into a wild plant garden. Sadly, my workplace has lost our lease on this space, and I suspect it will soon be swallowed again by the vinca

  8. Thankfully, we are so far behind up here, as far as gardening trends, that the groundcover movement, as represented by vinca, pachysandra, etc. never gained much traction. That and the plants were not hardy. A blessing in disguise, I suppose.

    Christine in Alaska

  9. Thomas, your post makes me think about how consistently we can learn from nature and extrapolate those learnings into all our relationships--not only with the gardens we tend, but with the people and communities with whom we share our lives. There's something so provocative about the issue of "invasiveness"--makes me think of the ways that we as human beings can take over or invade space in ways that are harmful...and the fact that the plants you mention are meant to be "easy" or "low maintenance"--well, that could take me off on a whole other tangent! Thanks for your beautiful and informative writing!

  10. Hi, Not ALL uses of 'groundcover' need be " Groundcovers are chosen based on the assumption that the area will be ignored, abused, or abandoned." I rather like to use em for all the above! Albeit in a less monculture way!! See
    William Martin

  11. I see you are reading Vista on your list - what do you think?
    Re ground cover I have seen wonderful use of ivies on a woodland floor together with raised canopies and box balls - I am thinking of French gardens such as Maizicourt in Normandy. A different look to the delicious variety afforded by ferns and hostas and other shade lovers, but effective in its way. Thank you for the thought - provoking post.

  12. I love your blog and I am in sympathy with what you wrote here... although as I wrote in my own post about this, I would temper the message in my own application. However... that said, you have just the right amount of conviction to make a dent in our apathy. It has me thinking, too, even though I like the use of groundcovers.

    Invasive is as invasive does, and it depends on the actual conditions of our places whether some of these plants are a problem. I wonder if the interest in small theme gardens for bees and wildlife might be a step in the right direction... They are manageable changes for most gardeners.

  13. If understood correctly the problem is just like the National Rifle Association claim about guns not killing people, people do.

    Therefore, if people do not have time to keep up the garden, ground covers or whatever, the stupidity of the gardener, not the invasiveness or not of the chosen vegetation,

    I have addressed the issue in my intercontinental blog, without any fear of ruffling the tender feathers of the average fool gardener in those prairies and my own.

  14. LOVE this post! The first thing I did was tear out an entire bed of English Ivy when we moved in to our house 4 years ago! I could not believe that the people we bought the house from let it grow over half of the side yard choking out several trees. I know how devasting groundcovers can be but laying it out as "we don't want to deal with the land" is sooooo true! Bravo to you! Great blog! Nicole

  15. Very good issues covered here. I thought you might be interested in the "back to Eden film" You can google and watch for free, but the DVD has even more info. No I am not affiliated with the film. But Low maintenance is the outcome of his work. I am starting to use his method, due to the water shortage, and am all ready seeing a difference in my water bill, and work.

  16. Thanks Thomas- for asking the tough questions. This article gives perspective to someone like me in the retail nursery trade. Indeed I have many people asking for the ground covers and I often wonder where they get these ideas- and what does their landscape at home look like? Indeed people need to be more creative, but maybe it is up to the professional to help them. I worked at changing the way people think about their landscapes on a very small level as a landscaper. It is a tough fight to get a homeowner to see things differently- especially from their yard worker (who just happens to be an undercover designer and ecologist)! I put in a bunch of hard work for them and they still wouldn't get it! I have a vision and I think this is better expressed at a national level....what kind of campaign could we come up with? A campaign for more creative personal environments could also double as a campaign to get a new generation into the garden- a much needed message in the retail trade -at the very least.

  17. Great blog. Glad to find you! But please tell me you didn't recommend planting goldenrod. We've got serious invasive problems in rural eastern Iowa with that. Hard to establish diverse prairie restorations without it taking over.


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