Trees and Shrubs for Urban Yards

City of Kirkland - Natural Yard Care

Choosing the Right Trees and ShrubsBasic Steps

Map Your Garden Soil conditions Light conditions Wind direction Microclimate locations Access

Map Your Garden

Consider plant placement criteria to ensure putting the right plant in the right place to begin with!

NORTH

SW

Soil Conditions of the Northwest

• Glacial Till

• Hardpan• Outwash Soils• Lake/Marine Bed Soils• Volcanic Ash• Mudflows

Lead to clay soil, sandy soil or loam

•What causes the shade? Trees? Buildings?•Is there variable exposure?•Does the exposure change with the seasons?•How will your tree or shrub affect exposure for other plants – for your house?

Where is Your Sun?

Which Way the Weather?• Prevailing winds from southwest or north• What is exposed and what is protected?• Reflection from sun off light colored surfaces

east

south

west

north

• Sheltered areas – tender plants• Water features – warm the air• Brick or rock – radiant heat

Microclimates

Microclimates

You can moderate microclimates by planting trees and shrubs• Deciduous trees - shelter and shade in summer• Plant groupings can provide efficient windbreaks• Evergreen trees – warm up air around them in winter

www.worldagroforestry.org

• For maintaining the garden• For utilities – meter boxes, moving curbside cans• For maintaining your house• Minimize need for pruning!

Provide Access

Plant Choices

• Utilize climate zone maps• Group plants with same needs together in the garden• Know the ultimate height and width of plant• Choose plants with low water needs • Plant a diverse garden• Avoid noxious plants• Plant correctly• Mulch garden beds• Water properly

USDA and SUNSET ZONES

Washington State Zone Maps

Height and Width of Mature Trees and Shrubs• Read the plant tag • Visit sites with mature trees and shrubs• Less than ideal conditions could affect ultimate size of plants• Plant placement matters!

Group Plants with Like Needs• Drought Tolerance – Manzanita, Juniper, Redbud• Boggy Soil - Blueberry, Red Stem Dogwood, Serviceberry • Sun Lovers –Pine, Mock Orange, Crab Apple• Shade Lovers – Japanese Maple, Dogwood, Snowbell

More efficient to water

Soil conditions are similar

Plant PlacementNORTH

trees & shrubs for screening and wildlifeshadetree

patio

veggiegarden

compostingbins

lawn

rainbarrels

wintergarden

fern garden

PNW native border

herbs

Rain garden

Choose Low Water Need PlantsKnow a plant’s origin!

• Washington natives- wet winter, dry summer

• California and Mexico – dry and sunny

• Mediterranean – windy and sunny slopes

• New Zealand – small leaved plants to reduce

transpiration

Washington Natives California and Mexico

MediterraneanNew Zealand

Plan a Diverse Garden• Provide year round interest – fall color, winter structure,

spring bloom, summer fruit• Attract beneficial wildlife – birds, bees, bats and more!• Keep plants healthy – no monocrops

Wildlife Plantings• Build layers• Provide diverse types of plants Food – berries, seeds, insects, nectar Shelter – thickets, branches Nest Sites – sheltered areas, snags Water feature – bonus to include on site• Know your local fauna • Plant native plants

By Alan Vernon [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

Urban Wildlife PlantingsSmall Scale Trees – 15 feet in height

Serviceberry Vine Maple

Crabapple Cornelian Cherry

Urban Wildlife PlantingsMedium Scale Trees – 30 feet in height

Redbud

Japanese Black Pine

Dogwood

Avoid Noxious Plants!• Get to know your local noxious weed board and their list• Class A regulated weeds MUST be managed by law• Class B and C are regulated at local levels depending on need • Non- regulated Noxious Weeds not mandated for control but

recognized as a nuisance• King County Weeds of Concern – not regulated and not on the lists

but recognized as being problematic• Any weed can change status

Correct Planting Techniques• Amend entire planting bed or not at all –

trees and shrubs need to adapt to native soil

• Dig planting hole twice as wide as root ball and no deeper than root ball

• Remove burlap, cage or pot

• Open up roots carefully – spread out so roots do not circle around in planting hole

• Trim where needed to open root ball –use sharp, clean hand pruners

• Place root ball into hole – keep stem upright

• Backfill with soil – do not amend in planting hole

• Water in well even if raining – build berm around planting hole

Mulch the Garden Bed• Conserve moisture• Moderate soil temperatures• Keep weeds down Wood Chips – get free from arborists working in your area Leaves from your garden – keep in place Commercial Mixes with manure and wood shavings or sawdust

Year OneSpring – fall, when weather is dry.• When planting - Soak• Week 1 - Daily or every other day• Week 2 onward - 2-3 times per week unless extremely dry • Water until fall rains beginYear Two• Water deeply 1-2 times per week in summer or when rain is

sparse• How long and often will depend on soil and weatherYear Three• Should be established and need no supplemental water• In extreme heat/drought, consider deeply watering 1 time per

month

Establishing Drought Tolerance

Smart Watering Practices

• Time and measure water being delivered – tuna can test• Allow water to soak in slowly to avoid loss of water from

evaporation and wind• Allow water to soak in deeply – this will establish a more

robust and deep root system capable of tolerating drought• Water in the morning to avoid evaporation, and avoid leaves

staying wet through the night – less disease

Smart Watering Practices Irrigation Options

Soaker Hoses

Drip Irrigation

Automatic Irrigation Systems

Hand Watering

How Much Water Does Your Plant Need?• Root depth is variable by plant type• Root depth depends on soil conditions• Know your plant’s native environment • Feel the soil to determine moisture content• Check trees and shrubs in dry months – July and August

Garden Hotline – 206-633-0224 Great Plant PicksThe Plant ListKing County Native Plant Guide King County Noxious WeedsWashington Native Plant SocietyCascade Water AllianceTrees for SeattleXerces SocietyUSDA Forest ServicePollinator Partnership

Resources