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  This Issue:
    Last Minute Holiday
          Gift Ideas
    Computer Corner
    Arizona's Official
          Noxious Weed List
    Does Your Landscape
          Have A Drinking
    Irrigation Time Bombs
    Gambel's Quail
    Lettuce for the Cool
    Desert Milkweed,
          Fit for a Queen

2004 Valley Citrus Festivals

Master Gardener Journal  

E A R T H - F R I E N D L Y   G A R D E N I N G

Does Your Landscape Have A Drinking Problem?

Sent by Cathy Rymer, Master Gardener, Water Conservation Specialist-Town of Gilbert

Are your plants' leaves wilted or curled?

Are the young shoots on your plants shriveled?

Do you have algae or mushrooms growing in your lawn?

Do your plants' leaves appear to be yellowing with green veins?

Do your plants' leaves have a "torched" look to the edges (dry and brown)?

Have you tried to install plants only to have them fail after a few weeks or months?

If you answered "yes" to any of the above, your landscape-watering schedule may need to be adjusted.

As could be expected, one of the most common reasons for plant failure here in the desert is incorrect watering. During the cool weather of late autumn and winter, over-watering is a common problem. As temperatures drop, many residents forget to reduce their watering. Plants that are irrigated at the frequency they were in the summer are subject to root and stem rots. Soils that are too moist prevent the intake of nutrients through a plant's roots, resulting in yellowing leaves.

It's time to turn back the clock‹the irrigation clock that is. If you used a once-a-week schedule for watering in the summer, you can extend that period to once every two or three weeks in the winter. Landscapes that include native or desert-adapted plants may only need water applied once per month in the cool season. Dormant Bermuda grass only needs water once a month. Even lawns overseeded with rye need only be watered once per week when the weather is cool

When spring arrives and temperature climb, the frequency of watering must be increased to keep up with plants' water needs. For instance, if you were watering once every two weeks in the spring, then increasing the frequency to a single watering once weekly should be adequate during the summer months. Too much water in the high temperatures and humidity of the monsoon season can cause root and stem rotting. Soils must be allowed to dry a bit between irrigations for the best plant health. This could save on your water bills as well.

Regardless of the season or the frequency of application, it is critical to apply enough water when you do. Irrigate to wet the soil to the proper depth. Trees should be watered long enough to wet the top two to three feet of soil. For shrubs, wet the soil down 18 inches or so. And for shallow-rooted turf, groundcovers, flowers, and vegetables, wetting to one foot of depth is sufficient.

To determine the depth of wetting, push a soil probe (metal rod) down into the soil after irrigation. The probe will push down through wet soil but will stop when it hits dry soil. If water isn't getting down deep enough, increase the length of time you're watering.

Finally, when selecting plants remember to choose those that are adapted to the desert. They can tolerate wide swings in temperature, intense heat and sun, drought, low humidity, drying winds, alkaline soils, high salts, and pests. Plants not adapted to the desert struggle and often fail.

For more information on watering your landscape plants and programming your irrigation timer, ask for the booklet Landscape Watering by the Numbers. It's available FREE from your local water conservation office. Or visit

Photography: Courtesy of UA

Maricopa County Master Gardener Volunteer Information
Last Updated December 18, 2003, 2003
Author: Lucy K. Bradley, Extension Agent Urban Horticulture, University of Arizona Cooperative Extension, Maricopa County
© 1997 The University of Arizona, College of Agriculture and Life Sciences, Cooperative Extension in Maricopa County
Comments to 4341 E. Broadway Road, Phoenix, AZ 85040,
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