PLANNING A LOW WATER GARDEN
helping people plant right, water less and garden more
If you’re like many of my gardening friends, you may think the most satisfying way to plan a new garden is to visit a local plant sale and load up a wagon with appealing looking blooms. While I'm not suggesting you abandon impulse buying completely, if your goal is a beautiful garden that will thrive with only occasional water, then a little planning is in order.
Evaluate Your Site
There are many beautiful plants that thrive in full sun with little water, but one trait most of them share is a need for good drainage. If your garden soil is the heavy clay common to many parts of the west, then you’ll need to do some preparation. Amending the soil with compost to create space for air and water around the roots is one way to accomplish this, but unless you want to continue amending indefinitely, you should know that your soil will ultimately revert back to its natural state.
A better method is to plant your garden on raised mounds, or berms. Not only does this add a pleasing design element to the garden, but presto! Instant drainage. Berms settle over time, so plan on mounding the dirt higher than the ultimate height you are looking for. And remember, a series of uniform mounds is not the goal; vary the height and width of your berms to replicate the type of rolling topography that appears in nature. In a typical suburban garden, I find that a settled height between one and three feet looks good.
Research Before You Shop
There are many sources for western gardeners looking for low water plants. The Sunset Western Garden Book has been a gardening mainstay for decades, and lists over 2500 plants, along with all their cultural data.
Another great book for San Francisco Bay Area gardeners is Plants and Landscapes for Summer-Dry Climates. In addition to a wonderful plant glossary that includes stunning Saxon Holt photos, the book offers great information on understanding plant communities and the correct way to plant. Keep in mind that this book includes plants that are not necessarily low water, so be sure to check the cultural data included for each plant.
If you live in California, an often overlooked on-line source is WUCOLS data. Available on-line, WUCOLS stands for Water Use Classifications of Landscape Species and is part of an excellent irrigation overview provided by the California Department of Water Resources. The report includes a list of several hundred landscape plants and their water needs. It even breaks out water needs based on six regions, and provides a chart listing over 100 cities, if you’re uncertain how your region is categorized.
WUCOLS is particularly helpful in that it distinguishes between low water and very low water plants. Once established, very low water plants like some Ceanothus and Fremontedendron will often die if given any supplemental water, and at a minimum will have shorter life spans. For that reason, it is best to plant these in their own area where irrigation can be shut off completely.
Drought Tolerant Does Not Equal Low Water
As a novice gardener 20 years ago, I relied on the plant categories section in the front of the Sunset Western Garden Book to help me choose plants for my hot Southern California garden. I was often confused to discover that plants listed in the drought tolerant section were categorized as moderate water when I looked up their specifics. What kind of bait and switch was going on here? I’ve since come to understand that drought tolerant simply means the plant won’t die if its water is rationed; but that doesn't mean it will thrive. If you want a truly low water garden, aim for plants that Sunset or WUCOLS list as low water, not simply drought tolerant.
Think all Salvias are the Same? Think Again.
And the hardest lesson of all – you find a plant you like that has low water needs, only to discover that a different cultivar or variety is a moderate water plant. This is particularly true with salvias and ornamental grasses, two of my favorite low water plants. For example, Mexican Sage is a reliably low water salvia. Pineapple sage? Not so much. While full sized Fountain Grass is a great low water option, its slightly smaller but otherwise identical cousin Oriental Fountain Grass will be happier with moderate water.
So remember, a little time spent researching your plant choices will pay off in a healthy, beautiful sustainable garden.
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Many water agencies in California and other parts of the west are offering homeowners rebates for reducing lawn, switching to more efficient irrigation and installing smart controllers. Click here for links to water agencies.
> DESIGN
Just getting started? The landscape Design Center has articles and advice on planning your garden, including lawn substitutes and alternatives, low water plant combinations, habitat gardening and more, plus authors' links to landscape design websites and blogs that specialize in sustainable design.
> INSTALL
Ready to turn your ideas into a garden? The Installation Center has information on irrigating your landscape and planting techniques.
> MAINTAIN
Now that the garden is in, how do you keep it looking its best? The Maintenance Center has articles on keeping your garden happy and healthy over time.
