Xeriscape Principles - Castle Pines North, Douglas County, Colorado

Xeriscape Principles Harriette Einolf – Douglas County Master Gardener

1 Harriette Einolf-Douglas County Master

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COLORADO GARDENING CHALLENGES

• Low humidity

• Drying winds • Extreme,

fluctuating temperatures

• Heavy clay soils


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Xeriscape

• Originally coined by a special task force of

– Denver Water Department

– Colorado State University

– Associated Landscape Contractors of Colorado

• Derived from the Greek word “xeros”, meaning dry and landscaping: xeriscape

• Describes landscaping with water conservation as a major objective


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Xeriscape vs Zeroscape


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7 Principles of Xeriscape

1. Develop landscape plan that integrates irrigation and maintenance

2. Reduce turf and high water use areas

3. Sensible approach to soil amendments

4. Select appropriate plants for the site

5. Mulch the soil to reduce evaporation

6. Irrigate efficiently

7. Set up maintenance to use resources efficiently


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1. Develop a landscape plan

• Prevailing winds

• Sun and shade areas

• Slope orientation

• Wet and dry spots

• Existing trees, shrubs, flower beds


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1. Landscape Plan: Site Exposure

SOUTH

• Warmer, drier

• Extreme temperature changes

• Longer growing season

• Spring frost danger


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NORTH

• Cooler

• Year round shade

• Less extreme temperature changes

• Persistent snow cover

• Good for marginally hardy plants


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EAST

• Morning sun throughout the year

• Afternoon shade

• Protected from winter winds

• Moderate temperatures


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WEST

• Big temperature swings

• Late Fall and early Spring frost damage

• NW cold winds intensify damage


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1. Landscape Plan: Irrigation

• Minimize high water use areas

• Eliminate/minimize planting in difficult areas to water

• Group plants with similar water needs, cultural requirements

• Tailor watering to plants’ needs, site, exposure and season


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1. Landscape Plan: Water Zones

HIGH - 1 ½” average per week

• Kentucky Blue Grass

• Maple, Birch, Willow, Annuals

MODERATE- ¾” Average/week

• Some perennials

• Honey Locust, Bur Oak

LOW - 1” average per MONTH

• Blue Grama grass

• Gambel Oak, Sumac

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Harriette Einolf-Douglas County Master Gardener

2. Reducing Turf and High Water Use Areas


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2. Turf or NOT ?

• Play areas for tots, pets

• Provides unity to design

• Prevents erosion

• Reduces heat reflection

• Harvests water

• Recharges groundwater

• Sloping areas

• Areas narrower than 8 feet

• Irregularly shaped areas, corners

• Areas along fence

• Areas under trees and shrubs


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2. High Water vs Low Water Turf

Kentucky Blue Grass

• 35-56” annual water

• 20” annual for survival

• Sun or light shade

• Moist, well-drained soil

• Mow height 3”

• Unmowed height

4” to 36”

Blue Grama Grass

• 12-18” annual water

• No irrigation when established

• Sun

• Sand or clay soil

• Mow height 3-5”

• Unmowed height

12” to 18”


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2. Turf Alternatives: Turkish Veronica

• Full sun or light shade

• Good drainage needed

• Evergreen

• Mid-Spring bloom

• Ground hugging mat

• Light foot traffic

• Attractive year round


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2. Turf Alternatives: Wooly Thyme

• Full sun or dry shade

• Dry, well-drained clay soil

• Low to moderate water

• Blooms in Spring

• Low foot traffic

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2. Turf Alternatives: Persicaria Affinus

• Sun to light shade

• Tolerates poor soil

• Low water

• Late summer bloom

• Copper red Fall color

• 6” foliage - 10” flowers

• No foot traffic


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3. Sensible Approach to Soil Amendments


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Paths to Soil Improvement

• Improve soil by adding amendments

• Paths direct foot traffic

• Preserve and protect the soil by mulching

• Select plants best suited to existing soil

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3. SOIL: Soil Amendments

Benefits

• Increase water and nutrient-holding capacity

• Improve soil aeration

• Some act as fertilizers

• Some increase soil organic content

• Many different kinds

• CSU Fact Sheet 7.214

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3. Clay Soil

• Small pore spaces

• Drains slowly

• Alkaline PH

• Prone to compaction

• Repels surface water

• High water retention

• Don’t work clay soil when wet!


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3. Planting Trees in Clay Soil

• Do NOT amend the soil!

• Dig shallow, wide hole – so that top of root ball sits 2-4” above soil line

– 2 to 5 times as wide as the diameter of the pot

• Do not disturb the soil at the bottom of the hole; apply water and let it soak in

• Place the root ball in the hole, and return loosened soil around the tree

• Water regularly until tree is established


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3. Improving the Soil: Exceptions

• Many native plants like native soil

• In improved soils:

– Plants lose xeric characteristics

– May not bloom

– Won’t thrive


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4. Selecting Appropriate Plants


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4. Plant Selection

• Does the site meet the plant’s needs?

• What is the plant’s mature size?

• Does the site allow for its mature size?

• Is the plant available and affordable?

• Check CSU Fact Sheets for xeric choices


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4. Plant Select

Criteria for Selected Plants

• Grows well here

• Adapts to challenging climates

• Good pest resistance

• Long season of beauty

• Non-invasive plants

• Caution: not all are xeric

plantselect.org

• Plant Lists

• Downloadable designs

• Demonstration Gardens

• Extensive search


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Plant Select Grasses

Giant Sacaton Korean Feather Grass


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Plant Select: Perennials

Sonoran Sunset Hyssop

Sunset Hyssop Red Feathers Echium


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Plant Select: Ground Covers

Wine Cups Panchito Manzanita


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Xeric Plants

• Regular watering a must the first year to get established

• Don’t plant in wet spots

• After planting, water slowly but thoroughly

• Mulch after planting to retain moisture


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5. Benefits of Mulching

• Retains water in soil

• Insulates soil from extremes of heat and cold

• Controls erosion

• Prevents or minimizes weeds

• Reduces maintenance


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5. Organic Mulches

• Shredded bark, Cedar mulch

• Wood chips, chunk bark

• Chipper debris

• Compost

• Leaves

• Lawn clippings

• CSU Fact Sheet 7.214


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5. Inorganic Mulches

• Pea gravel

• Squeegee and crusher fines

• Gravel, river rock

• Crushed stone

• Decomposed granite

• Woven landscape fabrics

• Black Plastic


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6. Irrigate efficiently and employ sound watering practices


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6. Types of Irrigation

• Automatic sprinkler systems

• Drip Irrigation

• Soaker Hoses

• Hand watering


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7. Maintain your landscape

• Weeding

• Deadheading

• Pruning

• Sucker Removal

• Disease and Pest Management

• Irrigation System Maintenance


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7. Maintain Your Landscape: Weeding

• Weekly Garden/Weed Walk

• Weed the day after rain

• Using Glysophate (Roundup)

– Kills actively growing plants

– 24 hours needed to penetrate roots

– Works best in 70 to 90 daytime temperatures – Read label carefully

– Spray away from storm drains and creeks

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7. Deadheading

• Clip dead flowers before they go to seed

• Cut just above leaf node

• Focuses plant’s energy on foliage and flowers

• Saves weeding time

• Improves beauty of garden


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7. Pruning and Removing Suckers Pruning

• Late winter/early Spring is best time

• Prune dead branches

• Prune branches that rub together

• Prune outside tree trunk collar

• ext.colostate.edu/index.html – Search on Pruning

Removing Suckers

• Remove suckers ASAP

• Suckers sap energy from other tree growth

• Enhances beauty of tree


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7. Irrigation System Management

• Critical for water conservation

• Don’t rely on automatic timers

• Check your sprinkler system weekly

• Replace broken sprinkler heads and drips

• Install a moisture sensor: up to $100 rebate!


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7. Setting Your Irrigation System

• Best time to water plants

– Cycles start after 5AM and finish by 10AM

– Cycles start after 7PM and finish by 10PM

• Soak and Cycle for lawns and slopes

– Determine total amount of time needed

– Total time number of cycles = cycle time

– Set 2 or 3 cycles for the cycle time

– Allow 30 to 60 minutes between cycles

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7. Set Your Irrigation System: Lawns

• Best time to water lawns – Start cycles after 10PM and finish by 6AM

• For Kentucky Blue Grass – May and Sept: 1 inch per week – June: 1¼ inch per week – July and August: 1½ inch per week – October: ½ inch per week

• Water deeply and infrequently • Soak and Cycle for deep penetration • CSU Fact Sheet: Watering Established Lawns


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7. Watering Tips for Conservation

• Plant early in morning

• Transplant plants in Spring

• Focus water on plant roots

• Reduce the need for lawn fertilizers by proper mowing and grass recycling

– 3 inch length for Kentucky Blue Grass

– Mow to 2 inches

• Aerate lawns in Spring

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7. Aerating Lawns in Clay Soil

• Spring is best

• Soil cores should be 4 to 6” deep

• Core aeration adds air and improves water absorption and soil quality


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7. Dealing with Drought

• Don’t fertilize or prune when water is scarce

• Don’t apply pesticides

• Hold back water early in season so plants need less water during the hottest months

• Kentucky Blue grass may go dormant: it may turn brown but is not dead

• Restrict traffic on dormant turf to avoid damage


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7 Principles of Xeriscape

1. Develop landscape plan that integrates irrigation and maintenance

2. Reduce turf and high water use areas

3. Sensible approach to soil amendments

4. Select appropriate plants for the site

5. Mulch the soil to reduce evaporation

6. Irrigate efficiently

7. Set up maintenance to use resources efficiently


Gardener

Resources

• CSU Extension: ext.colostate.edu/index.html

– Fact Sheets and PlantTalk

• Douglas County Extension Office

– Hot Line for Residents with Questions

– 720-733-6935

– Mon-Fri 8AM-4PM April through September

• Plant Select

– http://plantselect.org/

Harriette Einolf-Douglas County Master

Gardener 50

Xeriscape Principles - Castle Pines North, Douglas County, Colorado

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