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R Re es so ou ur rc ce e- -e ef ff fi ic ci ie en nt t N Na at tu ur ra al l L

R Re es so ou ur rc ce e- -e ef ff fi ic ci ie en nt t N Na at tu ur ra al l L La an nd ds sc ca ap pi in ng g D De es si ig gn n ● ● B Bu ui il ld d ● ● M Ma ai in nt ta ai in n 2009 edition This guide is divided into sections for the Design, Building, and Operations & Maintenance phases of a project, plus Resources. W W WH H HY Y Y G G GO O O N N NA A AT T TU U UR R RA A AL L L? ? ? Landscape professionals from around the Northwest have contributed and tested these ideas for resource-efficient, sustainable, cost-effective landscaping. They can be applied to any landscape design or use, from conventional lawn- and-bed designs to native restorations to innovative urban landscapes. Integrating these ideas from the initial project design stage through construction and into long-term maintenance will reap the most benefits. Benefits • More attractive landscapes • Easier maintenance • Lower water, waste, and energy bills; less need for fertilizers and pesticides • Better storm water detention and filtration • Better air and water quality • Better habitat for wildlife and people • Higher property values 5 Steps to Successful Landscapes 1) Build healthy soil Preserve existing soil and vegetation (especially trees) where possible. Amend disturbed soils with compost. Mulch existing landscapes regularly with wood chip, coarse bark, leaves or compost. 2) Plant right for your site Fit landscape uses to your site’s conditions, and choose plants that need less water, have few pests, and thrive in the Northwest climate. 3) Water smart After building healthy soil and selecting low-water use plants, group plants by water need, use more efficient irrigation methods like drip and soakers under mulch, and design and maintain irrigation systems to reduce waste. 4) Think twice before using pesticides Proper plant selection, plant care, and integrated pest management techniques can practically eliminate the need for weed and bug killers, reducing health risks. 5) Practice natural lawn care Start with less lawn – put turf only where needed. “Grasscycling” (mulch- mowing), and proper mowing height, watering and fertilization techniques can save time and money. Resource-efficient Natural Landscaping: Design – Build – Maintain 2 D D DE E ES S SI I IG G GN N N P P PH H HA A AS S SE E E Use nature as your model Natural systems: • Recycle everything – water, waste, and nutrients – back into new life • Are diverse, and therefore dynamically stable (tend to recover from pests, weather, etc.) • Are defined by the resources (sun, soil, water) available on-site • Have inherent beauty: elegance, complexity, and balance Fit the design to the site • Assess site soils, sun exposure, drainage, water table, grading and slope stability issues. • Consider adjacent uses, nearby sensitive areas (wetlands and waterways, slopes, wildlife uses). • Identify existing vegetation, and preserve (especially tree root areas) wherever possible. • Involve owners and end-users in fitting the intended uses into the site’s conditions. • Involve landscape maintenance staff (or a maintenance expert) early in the design process. Start with the soil • Plan to protect soil around trees and preserved vegetation from compaction. • Plan to stockpile and reuse site topsoil, if practical. • Plan to amend disturbed soils with compost, prevent re- compaction, and mulch beds after planting (see Building phase). • Consider getting a site soil sample, and any imported topsoils, tested at a soil lab. Follow the lab’s recommendations, and verify proper installation. • Design landscape for recycling fall leaves and chipped prunings as mulch, and mulch-mowing (“grasscycling”) lawns, to help maintain long-term soil and plant health. Plan a composting or leaf/chip storage area on site. Choose the right plant for the right place • Select plant varieties that will thrive in your site’s conditions (sun, soil, water), the local climate, and that grow well together. • Select for low maintenance needs: low water and fertilizer needs after establishment, high resistance to pests to eliminate chemical use, and minimal mowing or pruning needs. • Select based on mature size, to minimize pruning. • Plan vertically in layers, like the forest: ground cover, understory shrubs, and trees. (Select low shrubs and limb-able trees where sightlines are important) • Use native plant communities where they fit the site conditions and design – they often thrive with less maintenance and provide wildlife habitat. • Plan native and natural “buffer” areas near waterways, slopes, and other sensitive areas. • Use trees. Generally, plant conifers on north side to block winter winds, and deciduous trees to south for summer shading and winter light. (Consider mature tree size – see “tree selection” in Resources.) • Select plants with multiple benefits, such as food (“edible landscaping”), habitat, shade, etc. • Maximize green in dense urban areas – in public spaces, on building walls and roofs, in street tree placement – see Seattle Green Factor urban design guidelines in Resources section. • Put lawn where it belongs: on sunny (or light shade to reduce water needs), well-drained, moderately sloped areas where needed for play or walking uses. Turf often requires a lot of maintenance and water, so choose other plant groups where turf is not necessary or won’t grow well (heavily shaded, sloped, or poorly drained sites). • Avoid invasive species – see www.kingcounty.gov/weeds Resource-efficient Natural Landscaping: Design – Build – Maintain 3 Slow the flow: manage and reuse storm water on-site • Conform to existing drainage patterns as much as possible in designing site grading. • Minimize hardscape (concrete etc.) in the landscape – use softer engineering or plants. • Disperse drainage from hardscapes and roofs by spreading it out to sheet flow into landscape areas. • Use Natural Drainage Systems to slow and filter runoff, such as: - Soil amendment with compost - Bio-retention swales, “raingardens” and planters - Curbless or curb-cut streets flowing to swale - Green roofs, green walls, and tree planting - Pervious paving for parking and paths - Other natural drainage techniques – see Resources • Store and reuse stormwater beneficially: - Soil amendment and infiltration is the most cost- effective way to store rainfall for landscape use. - Stormwater detention vaults/cisterns, if required, may be designed to feed filtration and reuse for toilet flushing or vehicle washing, or to store late spring storms for summer landscape irrigation. Design for water conservation • Build deep soil with compost. Mulch regularly. • Select low water use or drought tolerant plant communities – they need minimal or no irrigation after they’re established (2-3 years). This may allow sites to be built with no permanent irrigation – soaker hose, drip, or quick connect systems can be used during the establishment period. • Minimize turf and other high water use plants. Avoid narrow, odd shaped, or isolated turf zones – they’re hard to water and mow. • Reuse water: recycled water, greywater systems, and stormwater detention cisterns are all potential sources for landscape reuse. Just directing roof and pavement runoff into landscape soil helps. • Group and zone plants by water need – match these “hydrozones” to irrigation system zones. • Have irrigation systems designed, or designs checked, by an Irrigation Association certified designer (see www.irrigation.org). Tell the designer you want a water- efficient design. • Reduce irrigation system waste with: - Evapotranspiration-based central computer controllers; or for smaller systems, weather and soil moisture sensor based “smart” controllers - Rain shut-off devices; flow sensors (to shut off zone if pipe breaks); check valves to stop low head drainage; and more efficient “high distribution uniformity” heads - Adequate piping size to minimize pressure differences, or pressure-regulating valves on each zone in sloped systems. Keep any pressure variation to within 10-15% of working pressure. - Separate zones for turf, and for each hydrozone - Drip, soaker, or other low-flow emitters • Have designer prepare a landscape Water Budget, and plan to test the system during commissioning to verify efficient performance – to learn more, see Resources. Make it last – naturally • Write a Landscape Maintenance Plan that specifies integrated pest and weed management, turf and plant maintenance, soil building with mulch and mulch- mowing, and irrigation system inspections and maintenance. See Resources for maintenance plan examples. Resource-efficient Natural Landscaping: Design – Build – Maintain 4 B B BU U UI I IL L LD D DI I IN N NG G G P P PH H HA A AS S SE E E Minimize impacts, to maximize benefits • Protect tree root zones (twice the drip line diameter) and soil areas being preserved, by: - Fencing out vehicles, equipment and storage - Boring rather than trenching utilities past major roots - Where some equipment traffic is unavoidable, covering tree root zones with 4-6 inches of coarse wood chip (hog fuel) or crushed rock, or with metal plates. • Stockpile site topsoil uploads/Ingenierie_Lourd/ landscaping-guide.pdf