Paved with Good Intentions: 5 Reasons not to ‘Zeroscape’ your yard
With the ongoing water crisis, we are starting to see a lot of formerly lush landscapes suddenly transformed into barren rock-scapes under the guise of water conservation. While these newfound converts to environmentalism are well intentioned, doing a rock-only landscape is actually worse for the ecosystem, the climate, and the drought. I know that seems counter-intuitive but here’s why.
A classic scorched-earth, “zero-scape” yard.
Before I dive into these reasons, I’d like to point out that the only two landscape options are not a lush green lawn, or a post-apocalyptic dune-scape. There are hundreds of varieties of native and adapted plants that can be used to both reduce water use and provide for a wide range of ecosystem services.
So before you flip your strip, your front lawn, or your entire yard please consider the following:
1. POLLINATOR HABITAT
A butterfly enjoying the Women’s Council Butterfly Healing Garden.
Globally and across the US, pollinator populations are collapsing, threatening our food supply. Whether it’s a sea of Kentucky bluegrass, a field of gravel, or an asphalt driveway – these types of landscape treatments are no different in terms of their lack of habitat for bees and butterflies. A much better alternative would be to provide any number of native, low-water-use plants that provide essential food sources to our pollinator friends.
2. URBAN HEAT ISLAND EFFECT
Diagram from the Urban heat Island Wikipedia page.
Urban heat island effect is a well-documented phenomenon, where largely paved urban areas absorb increased amounts of solar radiation resulting in increased temperatures compared to natural/rural landscapes in the same region.
These hotter temperatures require buildings to use more energy for cooling, which in turn increases the consumption of fossil fuels and carbon emissions, which in turn continues to warm the climate creating more drought.
This is compared to vegetated surfaces, especially trees, which shade the ground surface and provide evaporative cooling via transpiration. And while at least some rock-scape renovations will at least attempt to keep the existing mature shade trees in place, the provision of irrigation to the trees is neglected, resulting in the ultimate death of the tree for lack of water. Rocking one’s entire landscape and killing trees to save water compounds the problem of urban heat island effect.
3. STORMWATER RUNOFF
Photo credit: The Institute for Local Self Reliance
Among the many services they offer, vegetated surfaces and their living soils act like a sponge, absorbing stormwater runoff and releasing it slowly back into the water-table, holding the water for use by plant roots where it is taken up into living plant material and slowly transpired back into the atmosphere which has a cooling effect and increases moisture in the air which will eventually turn into more precipitation. Removing vegetation, even if it’s in favor of rocks and gravel has two effects:
1. While technically permeable, this surface treatment destroys the roots and microbes in the soil that contribute to the soils ability to hold water.
2. The weight of the rocks combined with weed barrier fabrics compact the soil over time. Anyone who’s ever removed rock and weed-barrier fabric from a landscape can attest to the concrete-like soil they discovered underneath.
The result of this is increased runoff compared to vegetated, living soil.
During major storm events this precious water ends up in the urban stormwater system. Municipalities spend millions of dollars building and maintaining these systems, which are often inundated and overwhelmed during major storm events. The impacts of this are real costs relating to damage from flooding, and contamination from water moving across paved surfaces in urban areas.
4. CARBON FOOTPRINT
Image Source: Wikimedia commons, Gravel pit Debiny Osuchowskie.jpg
Let’s talk about where gravel comes from – it has to be mined, usually an open pit somewhere. This causes a lot of dust pollution which settles on our snowpack and causes premature melting of the snowpack, compounding our drought problem.
The mining and shipping process for gravel is also very carbon intense, coupled with the fact that removing vegetation means eliminating a carbon sink, and often releasing carbon stored in the soil and vegetation back into the atmosphere.
All of this results in more carbon in the atmosphere, increasing temperatures, and making the drought worse.
The cost to basically cut back on watering and mowing of your yard is $0. The cost for weed barrier fabric and rock mulch is currently somewhere between $1-$2/sf installed. For an average ¼-acre lot, with an average 3,000 sf front-yard and park strip the cost to do this type of ‘makeover’ would be somewhere in the $3,000-$6,000 range.
That would buy a lot of plants and composted mulch! The cost for a very basic irrigation system and a native seed mix is about the same if not less than this.
'ZERO-SCAPE' ISN'T EVEN A REAL TERM.
The term “Zero-Scaping” is actually just a misinterpreted slang version of the term “Xeri-scaping” which comes form Xeros, the Greek word for dry. People who generally use the term “zero-scape” are envisioning a rock-filled moon-scape devoid of plants.
A properly implemented low-water use landscape or a Xeri-scape reduces or eliminates the need for irrigation with the use of drought-tolerant, native and adapted vegetation. The resulting landscapes require very little water and maintenance while promoting biodiversity, and if designed correctly can be really beautiful.
The Weiss Residence is a great example of how native xeriscaping can achieve low-maintenance, ecologically-functional curb appeal.
Our firm makes an effort to center all our designs around this philosophy. To see more examples like the Weiss Residence, or to get started with your water-wise landscape today see our Outdoor Design and Ecological Landscapes pages. You can see how we apply wholistic ecological principles across municipal, residential, and commercial projects by visiting our comprehensive portfolio page.