Xeriscaping Design Principles: A Guide for Water Conservation in Landscapes

When folks hear the word “xeriscape”, they may envision a landscape with rocks, cacti, and succulents – basically your garden-variety desert, pun intended. And this is certainly one way to xeriscape, but it’s not the only way. There are also alpine xeriscapes, prairie meadow xeriscapes, tropical xeriscapes, and more! So if xeriscaping doesn’t have a defined look, what exactly is a xeriscape? By definition, xeriscaping is a style of landscaping or gardening that promotes the ecological conservation of natural resources through water-smart design principles. But to truly understand this concept, we have to delve into the origins, history, and principles of xeriscaping. Where did it come from? When did it start? And most importantly, why was it started?

Xeriscaping History

The Xeriscape Demonstration Garden at Denver Water Headquarters in Denver, Colorado. © Jeffery Beall, 2015

Xeriscape is a portmanteau of the Greek root adjective xeros (ξερός) meaning "dry" and the English noun "landscape". Hence, “xeriscape” essentially translates to “dry landscape”. The term was first coined in 1981 by Nancy Leavitt of the Denver Water Board as part of a sustainability initiative and partnership with the Xeriscape Task Force, later known as Xeriscape Colorado Inc. As a non-profit organization, Xeriscape Colorado Inc. was founded to promote water conservation in landscapes by educating the public on how to create a water-efficient landscape to conserve water and other resources. During the early 1980s, there was a strong media interest in the xeriscaping concept so the initiative quickly grew from its grassroots movement into a multi-state movement throughout the United States. By 1986, the sustainability initiative had grown so much that it required a regulatory authority on the federal level. And so, The National Xeriscape Council was formed in 1986 with the endorsement of congress members including Congresswoman Patricia Schroeder, who wrote a letter to Jim Grabow, the Chairman of Xeriscape Colorado Inc., and her letter reads as follows:

“I endorse the National Xeriscape Council, Inc. with a great deal of enthusiasm. In the semiarid areas of the West, the need to conserve water is extremely important. A limited supply of water and an increasing urban population also forces us to think more wisely about our natural resources. The concepts promoted by the Xeriscape Council, low water use landscaping, can make great strides in reducing outdoor water consumption while still providing for eye-pleasing results. I wish you good luck in spreading the word on water conservation.”

Even back in the 80s, there was a strong desire to achieve sustainability for future generations. And although The National Xeriscape Council was discontinued in 1993, the theory and practice of xeriscaping continues to live on in the hearts of environmentally-aware organizations, charities, and peoples throughout North America and around the World.

Xeriscaping Benefits

Xeriscaping serves a significant role in determining the environmental sustainability of a landscape and demonstrates synergetic advantages to both human and wildlife communities:

• Increases water conservation (50–75%).
  

• Decreases maintenance, labour and cost.
  

• Decreases soil erosivity and erodibility.
  

• Increases soil infiltration, percolation and aeration.
  

• Minimizes or eliminates fertilizers and pesticides.
  

• Reduces carbon emissions, chemical pollution and contaminants.
  

• Provides wildlife resources for beneficial organisms.
  

• Increases property value (10–25%).

Xeriscaping Design Principles

Bickham-Rudkin Park Xeriscape Garden Design Plans in Edmond, Oklahoma. © Oklahama State University Extension

Xeriscape design is established on the basis of seven ecological principles:

i) Water conservation

ii) Restricted turf areas

iii) Efficient irrigation systems

iv) Soil improvement

v) Mulching

vi) Drought-tolerant species

vii) Low maintenance design

The following section contains ideas and concepts for implementing these xeriscaping principles into an urban garden or landscape.

Water Conservation

• Group vegetation with similar watering requirements into hydrozones to increase watering efficiency.

• Apply water in the morning (before 10 AM) or in the evening (after 6 PM) when evaporation rates are lowest.

• Study natural contours and drainage patterns to prevent runoff and erosion.
  

Restricted Turf Areas

• Reduce water-thirsty turf by installing drought-tolerant grass mixes in areas with practical functionality to increase water efficiency and reduce evapotranspiration by 30 – 60%

• Groundcovers, rockeries and tiered gardens can be implemented to minimize turf grass.
  

Efficient Irrigation Systems

• Use a water-smart, efficient irrigation system such as drip irrigation to reduce evaporation and prevent moisture stress by supplying a slow, steady supply of water on the soil surface or directly into the root zone at a rate of 2.0-8.0 L/hr.

• Rain barrels, cisterns and green roof systems can supplement or replace irrigation.
  

Soil Improvement

• Add sustainable soil amendments to improve soil structure, infiltration, percolation and aeration.

• Soil amendments include compost, green manure, worm casts, and biochar.

• Analyze soil texture, nutrient composition, and pH with soil testing kits.

• Aerate dry (!) soil sparingly to facilitate gas exchange and prevent damage to soil aggregates.
  

Mulching

• Lay mulches over the roots but away from the trunk or crown.

• Mulches include compost, wood, bark, needles, leaves, straw, stones, and rocks.

• Incorporate mulch at the appropriate depth (5.08–12.7 cm); deep mulches can procure poor soil drainage.

• Organic mulches should be replenished every year to offset decomposition.

• Choose coarse-textured mulches over fine-textured mulches for optimal water percolation/infiltration.

• Avoid mulches that have been painted or chemically treated as many of these chemicals are phytotoxic to plants.

• Do not use landscape fabric or plastic as this can impede water percolation/infiltration.
  

Drought-Tolerant Species

• Incorporate drought-tolerant species with physical adaptations for dry, hot environments. Examples of drought-tolerant adaptations include a compact growth habit, deep root systems, and leaves that are small/narrow/evergreen/succulent/ glaucous.
  

• Select plants with climate, insect and disease resistance.

• Use species native to your geographic region whenever possible.

• Compact shrubs and herbs can help reduce pruning maintenance and costs.

• Avoid monocultures as this decreases biodiversity and increases pest virulence.
  

Low Maintenance Design

• Proactive maintenance includes judicious watering and fertilizing, replenishing mulches, weeding, prohibiting shearing, fixing broken irrigation, and mowing at the appropriate height (5.08–6.57 cm).
  

For more information on how to start your own xeriscaping project, check out Creating the Prairie Xeriscape (2013) by Sara Williams.

Did you know that Tree J Consulting also offers a 60-minute workshop on xeriscaping? To learn more, contact us today!