Plant Selection: Low Water Landscaping

Plant Selection for Low Water Landscapes - Historically, plants selected from a limited “palette” for specific aesthetic and some functional traits (i.e. shade) -Low water landscapes require detailed knowledge about adaptation during selection

Selection Criteria: Ornamental Type –Tree=>specimens, shade, screening, architectural effect; the “ceiling” –Shrubs=> specimens, screening, color; the “walls” –Perennials/bunch grasses/ground cover=> color, surface cover, texture

Selection Criteria: Environmental Traits Cold tolerance-either or Sun/shade requirements- how well does plant grow Pruning needs-nuisance issues Soil requirements- drainage, fertility Water requirements- drought tolerance

Our landscapes derived from northern Europe –High rainfall, natural grass, grazed swards –Imbedded trees, fringed with shrubs, annuals Why We Have What We Have Imported across the US, including the SW deserts

Why We Have What We Have Current paradigm: –English landscape with extensive use of turfgrass across country Works well –The grass sward works well for recreation and park areas –Often used mindlessly as the sole option in surface cover

Most non turf plants also derived from high rainfall climates Why We Have What We Have –Trees are popular, and big trees only found where there is high rainfall; mesic climates. Attractive shrubs also from mesic climates –Woody plants from mesic climates easy to propagate and grow in nurseries, landscapes –Annuals chosen for color

Components of Low Water Landscaping: Design Practical design aspects of low water landscaping –Non uniform plant layout –Hardscape that does not require irrigation –Spacing that provides plants with more rooting volume Qualitative design aspects –Creating and honoring a sense of place –Recreating or being inspired by natural patterns

Components of Low Water Landscaping: Plant Material Practical aspects: choosing drought adapted plant material –By designing in space and non-uniformity, any plant can be more drought tolerant Qualitative aspects –Creating (reinforcing) a sense of place –Telling a story and giving meaning

Intermountain West Native Plants: Sources Again, using drought-adapted plants suited to particularly dry conditions requires careful knowledge of a particular species’ requirements Adaptation can vary within a species depending on geographic source of seed

Intermountain West Native Plants: Sources Cultivars- (CULTivated VARiety) are selected from within a species for certain traits, mostly ornamental but sometimes environmental; Seed stock-plants grown from seed, genetically –Genetically uniform plants creates uniform look and behavior, but may be susceptible to disease attack=monoculture –Genetically diverse plants closer to natural state, but may be uneven in terms of appearance

Intermountain West Native Plants: Selecting Tremendous craving for new plants in horticultural circles, both cultivars and species Most of US has been exploited for horticultural plant material; Intermountain West is relatively undiscovered regarding horticultural potential –Utah has 3,000+ species, many perennial wild flowers; undiscovered horticultural treasure trove

Intermountain West Native Plants: Sources of Problems LA’s, landscapers who think they know what they are doing, but don’t –Interpret natives/low water=day lillies, dogwood –Using native low water plant indiscriminately regarding how individual plants work together, availability

Intermountain West Native Plants: Selecting Plants are difficult for general public to make sense; native and drought adaptation even more difficult 40 best Utah native species for promotion have been selected: Plant Select –Few trees, since few trees are native –Mostly shrubs and perennial wildflowers –Most generally available, relative easy to produce and will stay alive in landscapes

A word about watering New transplants of even very drought-hardy species need weekly watering until root systems become established. Establishment can take a month to a full season, depending on species and time of transplanting. Grasses and perennials establish quickly, while shrubs and trees generally take longer. Very low water use – deep-water 1-2 times a summer during drought Low water use – deep-water every 4-6 weeks Medium water use – deep-water every 2-4 weeks High water use – deep-water every 1-2 weeks After Establishment