Water Conservation in the Landscape - University of Idaho

1. CIS 990
WATER CONSERVATION
IN THE LANDSCAPE
J. & ROBBINS, t FINNERTY, AND S. M. BELL -
Increasingnumbersofgardeners want water per day com
to use environmentally safe and energy- pared with the na
conservingpractices to maintain healthy, tional average of
attractive landscapes. Their desire has 147. The popula
produced a type of landscaping that tion of Idaho is ex
reduces wateruse and maintenance, pro pected to grow by
30 percent in the
tects water quality, and decreases pest
controlneeds while itincreases thehealth 1990s, increasing
the need for afford
and beauty of the surroundings. Water
able, consumable
conservation in the landscape is an es
water of high qual
sential part of anenvironmentally sound
ity. Conservation To reduce lawn expand patio space. Use brick or deck to
approach to gardening.
can helpensure that allow air and water to reach the root zone of trees.
By using the principles outhned in water will continue to be available. maintain attractive, healthy, and en
this publication, you can make more joyable yards and gardens. Water con
Landscaping practices also affect the
efficient use of water and still provide servation does not mean replacing all
quality of our water. A recent Environ
beauty and satisfaction in the landscape. lawns with pavement or having only
mental Protection Agency study found
As the demand for water increases, wa
that nitrates - an ingredient in many cactus and rock gardens! Your exist
ter-efficient landscaping will help con
fertilizers and a common home lawn
- ing landscapes already may incorpo
serve this limited resource. were chemical pol
and gardenherbicide rate one or two water conservation
lutants of groundwater. ideas. With a little extraeffort, you can
Idaho -
implement an entire water-wise land
first in wateruse Landscape water scape and significantly reduce water
use. Water-wise gardening involves:
Idaho is number one in per capita
consumption of water in the United
conservation * Design that stresses water conser
States. Idaho residents and nonagri You can take many steps toward vation
cultural businesses use 311 gallons of becoming a careful water user and still * Soil analysis and preparation
BEFORE
AFTER
- -
*
4-.
*T
r-t
Use mulch around trees and to gracefully extend the edges of shrub and tree zones Into former lawn space.
* Unlversityot Idaho
Cooperative Extension System 0 Agricultural Experiment Station

2. * Practical irrigated lawn areas
* Appropriate plant selection
* Effective and efficient water man
agement
* Use of mulches
* Proper landscape maintenance
Design that stresses water
conservation
To create a water-efficient land
scape, start by making a sketch of
existing structures, shrub areas, trees,
and lawns. Decide what changes you’d
like to make based on potential use of
the area, sun exposure, maintenance
level, water requirements, water avail
ability, personal preference, and land
scape budget.
Group plants by water need, pre -
ferred soil type, microclimate, and
maintenance requirements. For ex Before: The large lawn requires frequent watering, and many shrubs are poorly
ample, you could group plants requir adapted to a dry climate.
ing little water in an area that will not Spread organic matter such as shred cies and to develop grasses with lower
be irrigated frequently or in an area ded bark or leaves, straw, peat moss, water requirements, such as turf-type
with sandy soil, which will not retain compost, sawdust, and grass clippings tall fescue.
moisture. A microclimate is an area 2 to 3 inches deep on the surface of the Consider easeandefficiency ofwa
with a specific climate due to its loca soil and thoroughly till it in. Bark, tering when deciding on lawn size,
tion, such as the cool, shady, north side leaves, straw, and sawdust take extra shape, and location. Out-of-view prop
of a structure. Choose shade-adapted nitrogen to decompose. Add nitrogen erty perimeters such as road and drive
plants for this microclimate. Sketch along with these materials, especially way edges can be planted with drought-
out how the area will look when it is if you add them in spring. Nitrogen tolerant grasses and ground covers or
finished. You can complete the design will speed decomposition and prevent mulched with attractive rock or bark.
gradually over several years. a possible nitrogen deficiency in the Irrigating long, narrow grass areas and
plants you grow in the area. You could small, odd-shaped spaces is often an
Soil analysis and pseparatlon also compost these materials before inefficient use of water. A mulch or
Study the soil carefully, and match addingthem to the soil, decreasing the ground cover other than grass may be
plants with their preferred soil type requirement for extra nitrogen. the best choice for these areas.
and pH. Light. sandy soils fail to retain Preventing compaction and provid Patios and decks are useful instead
nutrients or water as well as clay or ing mechanical aeration increase the of lawn for outdoor living areas. Shrub
loamy mixtures. Clay soils may have ability of the soil to absorb and store beds and ground covers instead of lawn
poor aeration and drain poorly. Some water. can create an attractive visual effect.
plants grow in clay better than other
plants do. Practical irrigated lawn areas Appropriate plant selection
Adding organic matter to the soil Lawn grasses require more frequent
Select plants adapted to the growing
conserves water and improves any soil watering and maintenance than most
conditions. These plants should thrive
as it increases overall plant health. other landscape plants. Carefully con in the soil, be adapted to the climate
Organic matter added to sandy soil sider the intended use of the yard be- cold hardy and able to withstand sum
helps to absorb water and nutrients fore deciding how much lawn to in mer temperatures, and have a good
and to hold them in the root zone. stall. level of resistance to the diseases and
Organic matteralso loosens heavy soils Choose the grass species carefully. insects common to the area. Many
and improves drainage. aeration, and Much research is being done to deter native species are well adapted and
workability. mine water requirements of grass spe need little irrigation.

3. pings or of inorganic materials such as
rock and permeable or impermeable
plastic sheeting. Impermeable plastic
mulches can decrease soil aeration and
encourage shallow rooting, while rock
can compact the soil and heat up an
area. Fine mulches, such as sawdust,
may also encourage shallow rooting.
All mulches conserve water by re
ducing soil moisture evaporation and
weed growth. Organic mulches pre
vent soil compaction, add organic
matter, and moderate soil tempera
tures. Rock and plastic sheeting do
not. Inorganic and organic materials
are often combined. For example, per
meable plastic sheeting can be cov
ered with a bark layer.
Ptcper landscape maintenance
To reduce water use in the land
After: Lawn has been replaced by payers, mulched shrub areas, and plants with low scape, check the sprinkler system peri
water needs, making the area water conserving as well as low maintenance.
odically especially if it is an under
Many well-adapted exotic plants however, they adapt to less frequent ground system, time insect and dis
also are available and require low wa watering. Most well-established trees ease control correctly to reduce plant
ter input. Limited use of annuals, which and shrubs require several deep stress, and eliminate weeds.
generally require heavy watering, can waterings in the root zone during the Proper maintenance of the lawn is
provide summer color. growing season moist to a depth of 12 critical. Mow the grass at the recom
to 18 inches. Applying the proper
Effective and efficient water amount of watercan take several hours,
especially for large trees. The actual "Xeriscape," a term patented
mans time depends on soil characteristics by the National XeriscapeCoun
Apply water so that it is available to and the irrigation system. Soakerhoses cil, emphasizes the use of
the plants. Applied too rapidly, water and drip irrigation work well for this drought-tolerant xeric plant
is lost to runoff. Applied on exposed, type of watering. species combined with creative
unmulched soil, water evaporates. Drip irrigation or pop-up sprinklers landscaping practices to conserve
Other causes of wasted water are that apply water directly to where it is water. "Mesiscape" originated in
evaporation into the air from sprin needed are extremely water efficient. Massachusetts where the climate
klers and runoff from nonabsorbing Use them throughout the landscape is moderately moist mesic, but
areas, such as sidewalks and streets. when possible. water quality and quantity are
The greatest waste of water is ap Run sprinklers between late evening still critical factors. Mesiscape
plying too much, too often. Not only and midmorning to reduce waste emphasizes using landscape tech
does this practice waste water, but it through evaporation. Mechanical or niques that enable moderately
leaches nutrients deep into the soil and electronic timers on hoses, drip lines, drought-tolerant plants to grow
away from plant roots, increasing the and sprinklers turn off the water auto in dry conditions. Xeriscape and
chances of polluting groundwater. matically after the desired amount has mesiscape apply to Idaho with
Water lawns infrequently but deeply been applied. its dry environments inthe south
moist to a depth of 12 inches. Deep, ern and central regions and sea
infrequent watering promotes a deeply Use of mulches sonally moist northern environ
rooted lawn that is more water effi Mulch is a layerof nonliving mate ments. Xeriscape and mesiscape
cient and more drought tolerant. rial that ôovers the soil surface. This include many techniques for
All trees and shrubs require fre layer may be composed of organic merly associated with low-main
quent watering for a year or two after materials such as bark, compost, wood tenance landscaping.
planting. After they are established, chips, straw, sawdust, and grass clip-

4. mendedheightforthe species. Heights less water to become established dur tions. Contact Bob Mahler, Depart
of 2 to 3 inches allow the grass to ing this cooler period and can develop ment of Plant, Soil and Entomo
develop a deep, water-efficient root deeper, water-absorbing roots before logical Sciences, College of Agri
system. This taller grass forms a living the onset of warm summer weather. culture, University of Idaho, Mos
mulch, shading the ground to reduce cow, ID 83844-2339.
soil moisture evaporation and retard Further leading Books:
ing weed growth. As the grass grows University of Idaho Cooperative Ellefson, C., T. Stephens, and D.
taller and matures, it requires less wa Extension System publications: Welch. 1992. Xeriscape gardening:
ter and less frequent mowing. Leaving To order, contact the University of water conservation for the Ameri
grass clippings as a mulch improves Idaho Cooperative Extension System can landscape. New York:
soil structure, soil fertility, and water office in your county or write or call Macmillan Publishing Co.
retention. Clippings do not cause - Agricultural Communications, Idaho Knopf, J. 1991. The Xeriscape flower
thatch in lawns. Street, University of Idaho, Moscow, gardener: A waterwise guide for the
Fertilize only as often as necessary Idaho 83844-2240 208-885-7982. Rocky Mountain region. Boulder,
to maintain a healthy, green landscape. * CIS 168, Landscape Your Home Colorado: Johnson Publishing Co.
Avoid lush, rampant growth. Timing Grounds, 350 The authors Jo Ann Robbins, Ex
-
of fertilizer applications will depend C’S 731, Thatch in Lawns, 25o
tensiOn agricultural agent, Blame County,
on the plants in the landscape and the Hailey; Terry Finnerty, Extension associ
CIS 837, Mulchesfor the Home Land ate, Department of Plant, Soil, and Ento
existing fertility ofthe soil. Have a soil mological Sciences, Sandpoint Research
scape and Garden, 35o
test run every 3 to 5 years to determine and Extension Center, and Susan M. Bell,
the need for nutrients. Moderate use of CIS 858, Using Bark and Sawdustfor Extension agricultural agent, Ada County,
fertilizer can save time, labor, money, Mulches, Soil Amendments Boise. Artwork on page 1 reproduced by
and water. It will also reduce the po and Potting Mixes, 350 courtesy of The National Arbor Day Foun
CIS 887, Idaho’s WaterResource, free dation, Nebraska City, NE. Illustrations
tential for groundwatercontamination. on pages 2 and 3 reproduced by courtesy
Seed new lawns and plant new plants WQ- 1, Activities in Water Quality, of Sunset Publishing Corporation, Menlo
in the early spring. New plants require free Unavailable from Ag Publica Park, CA.
Issued in furtherance of cooperative extension work in agriculture and home economics, Acts of May 8 and June 30, 1914,
in cooperation with the U.S. Department of Agriculture, LeRoy D. Luft, Director of Cooperative Extension System,
University of Idaho, Moscow, Idaho 83844. We offer educational programs, activities, and materials without regard
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