SummerTree Institute

Making Environmental Education Irresistible

How to use our Water-Wise Plant Data Base

Finding Your Perfect Landscaping Plants

You will love searching here for the best plants to satisfy your landscape needs for your Southwest yard! Our Water-Wise Plant Data Base includes hundreds of plants, both native and non-native, that are water-wise, drought-tolerant, available at Southern California nurseries, and that are cold-hardy in our cool desert winters but still stand up to our extreme summer heat. We have included a special category of California Native Plants, so gardeners who want to grow plants native to our area can find them all in one location in our database. See below for a discussion of USDA Hardiness Zones, Sunset Climate Zones, and cold hardiness, and how they each relate to our region.

Click on “Simple” search to find a specific plant by name or to enter a particular attribute you are looking for. Click on “Custom” search to pick from a list of 18 attributes to fine-tune your search for exactly the kind of plants you are looking for.

USDA Hardiness Zones

USDA Hardiness Zones are based on the average annual minimum winter temperature. This system divides North America into 11 separate zones. Each zone is 10°F warmer, or colder, in an average winter than the adjacent zone. Zone 1 is the coldest; zone 11 is the warmest. In the Mojave Desert, we are predominately within USDA Zone 8, based on our winter low temperatures that indicate where a plant may survive the winter. Our lower, Colorado Desert is predominately within USDA Zones 9 and 10. To find your own USDA Hardiness Zone, enter your zip code in our “USDA Hardiness Zone Finder”.

Sunset Climate Zones

Sunset Climate Zones are based on the combination of climatic factors that affect a plant’s total performance, including length of growing season, timing and amount of rainfall, winter lows, summer highs, wind, and humidity. Sunset climate zones indicate where a plant will thrive year-round. Sunset magazine classifies 33 western zones, numbered from harshest (Zone 1) to mildest (Zone 33), and organized by region from north to south. The boundaries of each of these unique zones are a function of six geographic and climactic factors: latitude, elevation, ocean influence, continental air influence, mountains and hills, and local terrain. Taken together, these factors determine what will grow well in your garden and what won’t. In the Mojave Desert, we are predominately within Sunset Zone 11 (“Medium to High Deserts of California”), based on many climatic and geographic factors that influence where a plant may perform the best year-round. Our lower, Colorado Desert is predominantly within Sunset Zone 13 (“Low or Subtropical Desert Areas”).

Cold Hardiness

Cold Hardiness is shown in degrees Fahrenheit. This is the minimum temperature the plant can tolerate without suffering lasting damage.

Water use, sun exposure, soil preference, bloom times, and ideas for landscape uses are included for each plant. Special features are listed for each plant, such as whether the plants attract hummingbirds, butterflies, pollinators, birds, or wildlife; if they are rabbit or deer resistant, if they are pool or patio friendly, grow in containers, or have good flowers for cutting.

All plants are searchable by any number of the following attributes, so you can pick the attributes that you are looking for to find your perfect plant:

  • Common Name
  • Scientific Name
  • Water Use (Very Low, Low, or Moderate; we have not included plants here that require only high water use)
  • Soil Preference (Sandy, rocky, gravelly, well-drained, dry, clay, loamy, etc.)
  • Life Form (Tree, Shrub, Perennial Sub-Shrub, Cactus, Succulent, Ground-cover, Vine, Ornamental Grass, or Annual)
  • USDA Hardiness Zone (based on the average annual minimum winter temperature). See discussion above.
  • Sunset Climate Zone (based on the combination of climatic factors that affect a plant’s total performance, including length of growing season, timing and amount of rainfall, winter lows, summer highs, wind, and humidity). See discussion above.
  • Cold Hardiness in degrees Fahrenheit (minimum temperature the plant can tolerate without suffering lasting damage)
  • Deciduous/Evergreen (Deciduous – drops leaves in dormant season; Evergreen – retains leaves all year)
  • Growth Rate (Slow, Moderate, Fast)
  • Landscape Uses (Accent; Border; Hedge; Climber; Screening; Windbreak; Ground cover; Mass planting; Background planting; Shade tree; Specimen; Container; Slopes; Erosion Control; Bank stabilization; Dry shade, Dry washes; Medians; Firescaping/Firewise; Butterfly gardens; Hummingbird gardens; Wildlife gardens; Bird gardens; Bee gardens; Rock gardens; Mediterranean gardens, etc.). Each of these landscape uses is searchable to find all the plants with that particular landscape use.
  • Plant Coverage (Data for each plant includes the plant coverage value, in square feet, needed for “Cash for Grass” or lawn replacement applications).
  • Height (in feet)
  • Spread (in feet)
  • Sun Exposure/Light Needs (Full Sun; Part Sun/Part Shade; Filtered Sun; Reflected Sun; Full Shade)
  • Flower Season (Spring, Summer, Fall, Winter, Year-round)
  • Bloom Months (January…December)
  • Flower Color (every color imaginable, plus inconspicuous)
  • Native to (California, other states, other countries, or continents). Knowing where a plant comes from helps to know its suitability for our region; plants that are pre-adapted to our southern California climate include plants from other Mediterranean climates, located in two bands around our planet between about 30° and 45° latitude north and south of the Equator, and only on the western sides of the continents within these two bands. These regions include southern and southwestern Australia, central Chile, the Western Cape of South Africa and areas around the Mediterranean Basin. While our inland southern California deserts are not strictly considered a Mediterranean climate such as our coastal California region is classified, our desert climate is still influenced by the same overarching pattern of hot, dry summers and cool, wet winters. Plants adapted to this regime are already programmed to survive our desert’s hot, dry summers with extended droughts, and our cool, wet winters.
  • Special Features (including Easy-care; Attractive foliage; Container gardening; Attracts wildlife, birds, butterflies, hummingbirds, or pollinators; Rabbit resistant; Deer resistant; Erosion control; Aromatic foliage or flowers; Moonlight gardens;  Flowers for cutting, Long bloom season; Fall color, Pool friendly; Patio friendly, Accepts clay soils, Drought-tolerant, etc.). Each of these features are searchable to find all the water-wise plants with that special feature.
  • Description (this gives the gardener a feel for the plant, its unique characters, what the foliage, flowers, and fruit look like, what its best landscape uses are, any claims to fame for the plant, and any interesting historic uses, among other notable features)