When I am selecting plants that I am not familiar with, knowing which zone my garden is in, can be really handy. Planting zones are mostly based on exposure to frost and cold temperatures. Of course, other variables are important too. But finding my zone is a good start. There are several zone maps on-line. Some will even allow you to look up your zone by zip code. In a region with a patchwork of microhabitats and planting zones, being able to zoom into my own zip code is helpful.
According to the USDA Interactive Zone Map, I am in zone 8b. This zone designation is based on data that shows that the coldest temperature per year ranges from between 15 º F and 20 º F.
According to the Sunset Cold Hardiness Planting Zone Finder, I appear to be in zone 10. The Sunset Planting Zone Map is much more detailed than the USDA Zone Map. Variables considered include elevation, time of year when precipitation events occur, how late in the year frost occur (according to locals we can get a hard frost in May after a warm spring), the number of growing days in a year, number of summer days over 90 º F in a year, and other variables. Since the Sunset Planting Zone incorporates more variables, it is a better indicator of which plants might survive here. I use the term might with care. The zone doesn’t say anything about other critical variables such as soil type, soil texture, sun exposure, wind exposure, watering frequency, site specific precipitation, and so on.
Armed with my zone information, I can now search the internet for plants that might grow in my zone. A brief search located the following sites that identify plants suitable for Sunset Zone 10.
Learn 2 Grow has a searchable database that returned 10918 results for Sunset zone 10. Results are presented in alphabetical order with a picture and description. You can narrow the results with filters for plant type (i.e. tree, shrub, herb, etc.), function, sun exposure, soil moisture, and water requirement.
Plant Search Online requires a subscription and is for professionals who order whole scale.
Gardening in Arizona features pages of plant lists with links for each species. The following lists are currently available for Sunset Zone 10:
Links for shrubs and trees went to a black hole called “This page is not known”. Maybe these links will be online in the future.
Grow Zone 9 and 10 Catalog offers tropical plants for sale that are suitable for USDA zones 9 and 10. I found a cold hardy banana on this page that looks tempting. I think that will be on my wish list. Herbs and spices that will grow in my zone look tempting too. Overall, their offerings were enough for me to want to move to USDA zone 10.
Monrovia Plant Catalog is searchable by USDA Zone, Sunset Zone, Plant Type, Light Needs, Deciduous/Evergreen, Water Needs, Plant height, Plant Spread, and Growth Rate, Growth Habit, Foliage Color, Flower Color, Flowering Season, Flower Attribute, Special Feature, Garden Style, Landscape Use, and Problem/Solution. When I searched for USDA Zone 8, a list of 875 plants came up. When I limited the list to “Low water needs” I got a list of 875 results. When I searched for plants for Sunset Zone 10, I got a list of 401 plants. The Sunset List is shorter, but plants that are less likely to survive in my garden were eliminated.
I am sure that there are many other equally wonderful online catalogs that are searchable by planting zone. I hope this information is enough for a new gardener to get started on finding suitable for their gardens.