water wise landscaping rick durham department of horticulture

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