I am providing a few slides for a colleague of mine for the Southern Colorado Sustainability Conference upcoming next week on November 18 and 19 in Colorado Springs.  The portion of the presentation I am providing is on Xeriscape and how it relates to residential applications and in particular residential retrofits.  In the provided slides, I focused on the following statement: Zeroscape IS NOT Xeriscape. There is a common misconception that many conclude about Xeriscape,it is that Xeriscape is a landscape of all rocks, no plant material.  The idea behind Xeriscape is to provide a landscape that is low maintenance and low water use.  A ‘Zeroscape’ concept would typically create a ‘rock’ landscape which may be less water intensive, but high in maintenance.  An all rock landscape can create high intensity of involuntary plant material (weeds).
In lieu of ‘Zeroscape’, I recommend a ‘Xeriscape’ alternative with xeric plant material (fairly dense spacing to decrease opportunities for involuntary plant material) and large boulders.  Unfortunately, the installation of large spaces of plant material carries a large initial cost.  This is where it is common for landscape designers and landscape architects to ‘fill’ the majority of the ‘negative space’ with Kentucky bluegrass.  Kentucky bluegrass is extremely water intensive. Kentucky bluegrass requires approximately 40” of water annually, yet homeowners water much greater than 40”.  Kentucky bluegrass certainly has its place in the landscape, but it should be limited. Locations where Kentucky bluegrass is still appropriate include ball fields, kid’s play areas, backyards, parks or areas where social gatherings occur.  Kentucky bluegrass performs better than most other turfgrasses in high activity areas where human traffic is prevalent.

Image from www.miniskips.net

There are many other areas that today are saturated in Kentucky bluegrass that could see water and maintenance savings by simply modifying their landscape to a different species.  Some such areas include street medians and office parks, where little to no human activity occurs.  The problems with Kentucky bluegrass extend further than the water use and costs.  Maintenance via lawnmowers of the Kentucky bluegrass areas can be quite costly in both dollars and time.  Most people will mow their lawns one or more times per week, resulting in high amounts of time. (See “
What is the ROI for Mowing the Lawn”)
For more information on other turfgrasses, see “Alternatives to Bluegrass for the Larger Areas in a Landscape”.
Interesting Environmental Fact about Lawn Maintenance from the EPA:  “A traditional gas-powered lawn mower produces as much air pollution as 43 new cars, each being driven 12,000 miles.”