Contrary to local garden geek beliefs (myself included), this year of unprecedented drought has brought to light that many plants thought to be drought tolerant, are certainly not. This includes Hebe, Crocosmia (Montbrecia), Rudbekia (black-eyed Susan) and Echinacea (purple coneflower).
I have composed my own drought tolerant list based on my observations in established gardens this year. They are listed according to drought tolerance in the sun or shade.
2015 Extreme Drought Tolerance List
Shrubs and Trees for Sun
Acer griseum-paper-bark maple
Acer rubrum-red maple
Arbutus unedo ‘Compacts’-dwarf strawberry tree
Actostaphyllos varieties and natives-manzanita
Carpenteria californica-Sierra bush anemone (native to Calif)
Ceanothus thrysiflorus-California lilac (native to Southern Oregon & Calif)
Cistus purpurea and other varieties-rockrose
Cotinus coggygria varieties-smoke tree
Cupressus-Some cypress
Juniperus-juniper
Lagerstromeria indica-crepe myrtle
Lavendula varieties-lavender, English & Spanish
Lonicera varieties-Honeysuckle shrub & vine
Nandina varieties, especially ‘Sienna Sunrise’, ‘Moyer’s Red’ & ‘Plum Passion’.
Rosemarinus varieties-rosemary
Roses-shrub and rambler
Senecio greyi varieties-ragwort
Perennials for Sun
Achillea varieties-yarrow varieties
Aescelpis-native milkweed varieties, butterfly weed
Artemesia varieties-wormwood
Erisimum linefolium varieties-wallflower
Helianthemum-rockrose
Kniphofia varieties-red-hot poker
Penstemon rupicola-rockery penstemon
Salvia varieties-hardy salvia or sage varieties
Santolina varieties-lavender cotton
Sedum varieties-stonecrop and of coarse, Yucca varieties
Shrubs and Trees for Shade
Camellia japonica & sasanqua
Choysia varieties-Mexican orange ‘Sundance’ & ‘Aztec Pearl’
Elaeanagus varieties-silverberry, Russian olive
Leucothoe varieties-drooping & Sierra
Lonicera varieties-shrubs
Mahonia varieties-Native Oregon grape and others
Ribes sanguineum-red flowering currant (native)
Sarcococca varieties-sweet box
Thuja plicata-Western red cedar (native)
Vaccinium ovatum-evergreen huckleberry (native)
Ferns, Groundcovers, Perennials and Sedges for Shade
Carex oshimensis ‘Evergold’-’Evergold’ variegated Japanese sedge
Dryopteris seteferum-Alaska fern
Epimedium varieties-barrenwort
Oxalis oreganum-native shamrock plant
Polystichum minutum-western sword fern (native)
Donna Giguere Landscape Design 