water wise landscaping rick durham department of horticulture
TRANSCRIPT
Water Wise Landscaping
Rick Durham
Department of Horticulture
Average residential water use increases 30% - 50% during the summer months when
citizens turn on their outdoor irrigation systems
Water Conservation Measures
• Summer Surcharge: Rate increases 25% to 100% when use exceeds average winter consumption.
• Rationing: Odd/Even outdoor watering
• Bans on Outdoor Use
• Solution: Economic Incentive + Education
This is equivalent to:14 five-minute showers
26 runs of the dishwasher72 flushes of the toilet9 full loads of laundry
One portable lawn sprinkler operating 1 hour uses 360 gallons of water
Coined by Denver Water in 1978, now
trademarked
From the Greek Word “Xeros”, which
means dry
(Pronounced (Pronounced Zera-scape)Zera-scape)
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Divide the Landscape into Three Water-use Zones
• High Water-use Zone (Oasis Zone)
• Moderate Water-use Zone (Transition Zone)
• Low Water-use Zone (Xeric Zone)
High Water-use Zone (Oasis Zone)
Small “high-impact” or high visibility area of the landscape where plants are provided their optimum water requirement at
all timeEntrance to the home or
business
Annual flowers
Moderate Water-use Zone (Transition Zone)
Plants are watered during establishment. Then, once
established, they are watered only when they show signs of water
stress.Shrubs, dogwoods, redbuds,
herbaceous perennials
Low Water-use Zone (Xeric Zone)
Once established, plants are provided no supplemental
irrigation, except during periods of extreme droughtJuniper, Oaks, Maples
Viburnums, Ornamental grasses
Goal of Water Wise Landscapes
Reduce and minimize the size of the area irrigated and
the frequency of irrigation
HouseD
rive
way
Street
EuonymusIteaLittle Gem
Magnolia
Native Trees
Spirea
Native Oak
Nandina
Turfgrass
N
High Water-use Zone
Modere Low
Low
Annuals
Ornamental Grasses
Daffodils/Siberian Iris/Daylilies
Mulch
Mulch
Year 1
High Water-use Zone
Low
Low
Low
Low
Moderate
Moderate
Hig
h
Year 1
Fescue
Liriope
Mulch
Year 2
Moderate
Water-use Zone
Low
Low
Moderate
Low
Moderate
Moderate
Hig
h
Low
Low
Low
Low
Year 2
Barberry
Purple coneflower
Year 3
Moderate
Water-use Zone
Low
Low
Low
Moderate
Moderate
Moderate
Hig
h
Low
Low
Low
Low
Year 3
Moderate
Water-use Zone
Low
Low
Low
Low
Moderate
Moderate
Hig
h
Low
Low
Low
Low
Year 4
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Urban soils
• Often lack topsoil
• Prone to compaction
• Organic matter is best remedy– Increases soil structure– Increases porosity and drainage– Increases water holding capacity
How Much Amendment to Use?
25% by Volume
3 inches incorporated to a 12 inch depth
1 cu. yd. / 100 sq. ft. = 3 in. on soil surface
1 cu. yd. = 27 cu. ft. = Nine 3 cu. ft. bags or thirteen 2 cu. ft. bags / 100 sq. ft.
Use only decomposed organic material (right) as a soil amendment
More plants are killed from More plants are killed from over-watering than from over-watering than from
droughtdrought
Possible Solutions to Poorly-drained Soils
Plant on raised beds Deep cultivation Install sub-surface drainage Select appropriate plants
Possible Solutions to Poorly-drained Soils
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
A few good “drought tolerant” plants
Annuals
Gazania rigens - Gazania
• Various colors, most bicolors, full sun
• 6-10 inches tall• Few pests• Good drought
tolerance• Individual flowers are
short lived but many flowers on the plant
Gomphrena globosa - Globe Amaranth
• Purple, orange, lavender, white flowers, full sun
• 12-48 inches tall• Few pests• Used as bedding,
border, cut and dried
Helianthus annuus - Sunflower
• Orange, yellow, bicolors, full sun
• 2-14 feet tall• Powdery mildew is
the biggest pest problem
• Used as border and cut flowers
• Attractive to butterflies, birds
Melampodium paludosum - Melampodium
• Yellow flowers, full sun to partial shade
• 24-36 inches tall• Few pests,
occasionally powdery mildew is a problem
• Used as bedding or border plants
• May reseed but not invasive
Petunia x hybrida - Petunia
• Many colors and bicolors, single and double flowers, full sun to part shade
• 12-16 inches high, some shorter
• Few pests• Used as bedding and
container plants• Fertilization and moisture
keep them looking good
Portulaca grandiflora - Moss Rose
• Various colors, full sun
• 6-10 inches tall• Few pests• Used in bedding and
containers• Very heat and drought
tolerant
Salvia faranacea - Mealycup Sage
• Blue or white flowers, full sun
• 18-24 inches tall• Few pests• Used as bedding
plants and as dried flowers (calyx)
Zinnia spp. – Profusion Zinnias
• Pink, orange, white, full sun
• 12-18 inches tall• Few pest, powdery
mildew resistant• Used as bedding and
container plants• A little more expensive
but well worth it
Perennials
Achillea - Yarrow
• Many colors, flower in late spring to summer
• 2-3 feet tall• Few pests• Borders, cut flowers,
dried• Cuttings or division in
spring or fall, some by seed
Aquilegia x hybrida - Hybrid Columbine
• Flower colors, many and bicolors, in spring and early summer
• 1½ to 3 feet tall• Leaf miners may make
foliage unattractive• Used in borders, will also
do well in part shade• Division in late summer,
seed
Asclepias tuberosa – Butterfly weed
• Flowers orange in summer
• 1-2 feet tall• Major pest – aphids• Used as a border plant
and for cut flowers, attractive to butterflies.
• Propagate by seed or root cuttings, does not transplant well.
Aster spp. - Asters
• Flowers in blues, violets, whites in summer and fall
• 1-6 feet tall, taller varieties must be staked
• Powdery mildew is the major pest
• Used for borders and cut flowers
• Propagate by division in spring
Baptisia australis – False indigo
• Blue flowers in late spring
• 3-5 feet tall• Few pests• Used in borders, dried
seed pods• Division in late fall or
early spring, seed
Echinacea purpurea – Purple Coneflower
• Flowers purple, white in summer to fall
• 3-5 feet tall• Major pest is powdery
mildew• Used as border or cut
flowers• Divide clumps in
spring or by seed
Hemerocallis hybrids - Daylily
• Many colors, bloom in early summer
• 8 inches to 3 feet tall• Major pests are
aphids and leaf spot• Used as border plants
or in mass plantings• Propagate by division
in late summer
Perovskia atriplicifolia - Russian Sage
• Blue flowers in summer
• 4-6 feet tall, shrubby• Few pests• Used as a border• Propagate by
cuttings, division, or seed
Rudbeckia fulgida - Black-eyed Susan
• Yellow flowers in summer to fall
• 2-3 feet tall• Powdery mildew is
the main pest problem
• Used as a border, cut or meadow flower
• Propagation by division or seed
Sedum spectabile - Showy Sedum
• Pink, red, white, lilac flowers in late summer and early fall
• 12-18 inches tall• Few pests• Used as a border, edging,
cut flower or dried• Propagation by division or
cuttings
Bulbs and other modified stem/root plants
Crocus spp.
• White, yellow, blue or bicolor flowers in early spring. Some fall blooming species as well
• 3-5 inches tall• Few pests• Used as borders• Propagate by offsets• Not a true bulb -
corm
Iris hybrids - Tall Bearded Iris
• Various colors and bicolors in late spring
• 2-4 feet tall• Main pest is iris borer• Used in borders• Propagate by division
in fall• Not a true bulb -
rhizome
Muscari armeniacum - Grape Hyacinth
• Blue and white flowers in spring
• 4-8 inches tall• Few pests• Used in borders and
as cut flowers• Propagate by offsets
Narcissus spp. and hybrids - Daffodil
• Yellow, white and pink, single and double flowers in spring
• 3-18 inches tall• Few pests• Used as border and cut
flowers, also containers• Propagate by offsets
and division
• Wildflowers, especially spring ephemerals
• Ornamental grasses
• Culinary herbs
Most food crops (vegetables and fruits) need plentiful moisture
Also consider:
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Use Turfgrass for a Purpose
• Aesthetic Value (Welcome Mat)• Recreational Surface• Erosion Control
Minimize the amount of irrigated turfgrass
Avoid Using Irrigated Turfgrass Just to Fill Space
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Drip IrrigationDrip IrrigationUses 30% to 50% less water than sprinkler irrigationAvoids spraying foliage so diseases are less likely to occur
No spray drift
Only need to water 25% of the root area
Reducing Reliance on Municipal Water Supplies
Through Rainwater Harvesting
Roof Catchment PotentialRoof Catchment Potential
Sq. ft. X catchment coef. X no. gal./cu. ft. area X feet rainfall
sq. ft. X 0.95 X 7.48 X 0.0208 (1/4 in. rainfall)
Catchment Potential Per 2,500 sq. ft. of roof area
¼” rainfall 369.5 gallons
½” rainfall 740.8 gallons
¾” rainfall 1110.3 gallons
1” rainfall 1479.8 gallons
Irrigation Needs½ acre lot: 21,780 sq. ft., 10% irrigated @ ½” /1,000 sq.
ft.2178 sq. ft. @ 300 gal./1000 sq. ft. = 653
gallons/wkAnother 10% of the landscape drip irrigated
50 drip emitters @ 1 gal./hr.: run 6 hours = 350 gallons/wk
Need 653 gal. + 350 gal. = 1,003 gal./wk.
Or 4,013 gallons to get you through a 4 wk drought
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Best MulchBest MulchOrganicOrganic
Fine-texturedFine-textured
Non-mattingNon-matting
Newspaper placed under mulch, 2- to 3-sheets thick, helps provide an added barrier to moisture loss.
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
When Managing a Water Wise Landscape, Avoid Frequent Flushes of
Vegetative Growth Brought on by:
• Fertilization
• Pruning
• Irrigation
FertilizationFertilization• Target fertilization to plants that need it.
Established trees and shrubs may not need to be fertilized annually.
• Use slow-release forms of nitrogen• Use low rates of fertilizer• Limit fertilization during dry periods
Too Much Nitrogen
• Increases pest problems
• Increases top growth
• Reduces root growth
• Increases pruning requirements
• Increases run-off into groundwater
Prune by selective thinning instead of shearing
GrasscyclingLet the Clips Fall Where they MayLet the Clips Fall Where they May
ClippingsAdd
NitrogenBack to theSoil
ClippingsHelp HoldMoisture in the soil
Clippings DO NOT Cause Thatch
Seven Steps of Xeriscape• Planning and Design
• Soil Analysis
• Appropriate Plant Selection
• Practical Turf Areas
• Efficient Irrigation
• Use of Mulches
• Appropriate Maintenance
Acknowledgements
Dr. Gary Wade
University of Georgia
Department of Horticulture