Desert Bioscaping - October 20, 2010
Jeff Schalau, Associate Agent, Agriculture & Natural Resources
University of Arizona Cooperative Extension, Yavapai County
“Desert bioscaping” is an ecologically-based approach to landscaping that conserves water, reduces energy use, provides wildlife habitat, and minimizes (or eliminates) the use of pesticides and fertilizers. The University of Nevada Cooperative Extension has promoted bioscaping in the Las Vegas area for several years. They have also created a simple guide that teaches the basic concepts and provides examples and ideas. The principles of desert bioscaping are sustainable, easy to understand, and can be readily applied to any Arizona landscape. Below, I have outlined a few bioscaping concepts.
Water harvesting has become a very popular garden topic and many local people have installed rain barrels and larger water capture and storage systems. While these systems are great, they can also be expensive. Passive water harvesting is another technique which simply shapes the land surface and directs surface flow to areas where water can be stored in the soil. The use of pavers and mulches also increases water infiltration. Pervious pavement is a newer technology that allows water to pass directly through paved surfaces to be stored in the soil. However you approach it, keeping naturally occurring precipitation from leaving your property conserves water.
Composting kitchen scraps, garden trimmings, and other suitable materials is another bioscaping practice. This reduces waste going to the landfill and is a ready source of organic matter and nutrients for garden and landscape plants. The resulting compost can be used as a soil amendment or surface mulch. If you have a turf area, keep it small and mow it with a mulching mower. In our desert climate, grass clippings will rapidly decompose on the soil surface reducing the need for fertilizers. I’ve heard all the excuses – forget about them and start composting.
Design your landscape to include deciduous trees that create shade during summer while allowing sunshine through during the cool season. This conserves energy and creates outdoor living space. Vines can also cool down temperatures, but avoid invasive and/or destructive species such as English ivy and Vinca major. Grapes and flowering vines are better choices. You can also select plants that are food sources to hummingbirds and beneficial insects to add interest to your landscape.
If you discover a pest problem, use integrated pest management strategies to minimize negative effects to non-target organisms. Correctly identify the pest, monitor it to determine if the damage is truly significant, and apply cultural and/or mechanical management strategies before reaching for a pesticide. Watch for natural enemies such as ladybird larvae, lacewings, and preying mantids before you apply insecticides. If you determine that a pesticide is necessary, select a least toxic product and apply it only to the affected area.
Many “garden experts” promote the use of nitrogen fertilizers on all landscape plants. This is a myth which is perpetuated by people that sell fertilizers. Nitrogen fertilizers promote leaf and shoot growth which often leads to weak wood and/or the need to prune plants excessively. Herbivorous insects prefer feeding on nitrogen-fertilized plants because they are more tender and nutritious. Roses, fruit trees, and turf are some exceptions and do require periodic nitrogen fertilization. Excess nitrogen is also a water pollutant and should be used with care near rivers, streams, irrigation ditches, and areas of shallow groundwater. Fertilize woody landscape plants only when they display nutrient deficiency symptoms.
Do not overplant your landscape. Plants need space to be healthy and they will occupy the site over time. If your property has native plants and undisturbed areas, incorporate these features into the overall plan. Once you disturb a native ecosystem, weeds usually invade the area. Research the mature size and shape of plants species to be used and ensure they will not touch your roof or interfere with utilities. Have your property “blue staked” before you dig to avoid damage to underground utilities – call 811 or go to www.azbluestake.com for more information.
There is much more to know about Desert Bioscaping. You can download the 21 page University of Nevada Desert Bioscape Guide at www.unce.unr.edu/publications/files/ho/2004/sp0412.pdf or go to this column the Backyard Gardener website for a live link.
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Last Updated: October 14, 2010
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