The Waterwise Garden

Coconino County Desert Beardtongue in a waterwise garden


by David Salman, Founder and Chief Horticulturalist at High Country Gardens 

Xeriscaping, also known as waterwise gardening, is a gardening style that has applications to most parts of the country, not just those living in desert regions.

By choosing plants that are well matched to a region's precipitation, along with other factors (such as soil type, soil pH, and climate), a landscape will be colorful, waterwise and low maintenance. Thus, learning about a plant's preferences and then matching these preferences to local conditions will greatly improve its performance. This is what is meant when garden experts recommend using "regionally appropriate" plants.

Plus, we’ll share the best strategies for protecting your waterwise plants.

Matching Plants to Your Region's Precipitation

us rainfall mapus rainfall map

Looking at a rainfall map of the continental United States it is plain to see that rainfall varies dramatically across the country.

For example, the western edge of the Pacific Northwest is famous for its rainy weather; and the map indicates the rainfall here ranges between 50" to 60+" annually. But what this map doesn't tell you is that while this area of the country is soggy from late fall through spring, it's quite dry during the summer and early fall.

As another example, in the high desert of Santa Fe, NM we average 11 inches in a good year. Approximately 60% of it comes as thundershowers in a six-week period during July and August. Winter snows and occasional spring showers deliver the remainder. 

Does the seasonality of a region's rainfall influence plant choices? Much of the time it doesn't, but there are a few exceptions.

For example, regions with Mediterranean climates have wet winters and dry summers, including California and the Pacific Northwest. Plants native to these regions are genetically programmed to go dormant or semi-dormant in the summer, when their habitats are driest. However, in irrigated garden settings, xeric non-native plants that originate in regions having summer rainfall can offer better summer garden performance. Chihuahuan desert natives like Salvia greggi 'Furman's Red'Penstemon psuedospectabilis (Desert Beardtongue) and Agastache cana (Texas Humingbird Mint) are excellent choices because they will grow and bloom when the west coast native flora wants to be dormant.

As a general rule of thumb, it is often easier to take plants native to wetter regions and grow them in drier regions. In the extreme, however, it is not a waterwise strategy to take species that need marshy conditions and move them to the desert.

Agastache Cana will grow and bloom when west coast native flora wants to be dormant.


Matching Plants to A Range of Garden Conditions

Average quality soils that are near to neutral in pH (slightly acidic or slightly alkaline), aren't overly fertile and drain well are suitable for a wide range of plants. Given decent soil to grow in, plants during the spring and summer growing periods can tolerate more rainfall than they might normally receive in their native habitat.

However, this is often not the case in winter, when the plants are dormant. Too much water in freezing winter conditions can be detrimental. When growing a plant in cold weather situations that are much wetter than the plant is accustomed to, it is necessary to provide modified conditions to protect the plants from excessive winter/early spring moisture.

As in all things, moderation is the key. Plants don't mind being in conditions that are somewhat wetter or drier than their native habitats given other conditions like cold hardiness, soil conditions and sunlight requirements are also suitable.

Strategies for Protecting Waterwise Plants

  • Soil Drainage: Providing excellent soil drainage is at the top of the list. This can be accomplished by planting in naturally very sandy soils or by adding a lot of coarse sand (at least half by volume) to the existing soil and mounding it to create a bermed bed.
  • Raised Beds: Making raised beds using sandy soils is another effective method of greatly improving drainage.
  • Planting Site: Different planting sites can have drier or wetter conditions as well. Planting in full sun on the south and west sides of buildings will take advantage of these naturally hotter, drier sites. North and east facing sides of buildings and walls are shadier and will be much damper and less well suited to moisture intolerant species.
  • Cold Frame: If you're really bound and determined to grow xeric plants in an area with wet winters, move a cold frame over small beds for the winter or fabricate a plastic-covered bamboo frame over individual plants. Many rock gardeners in England cover their prize winter moisture sensitive specimens with a pane of glass to keep the soil around the plant's roots dry.

As a general rule of thumb, it is often easier to take plants native to wetter regions and grow them in drier regions. In the extreme, however, it is not a waterwise strategy to take species that need marshy conditions and move them to the desert.

Shop Waterwise Perennials

  1. Blue Ceratostigma plumbaginoides, Ceratostigma plumbaginoides, Hardy Plumbago

    Hardy Plumbago (Ceratostigma plumbaginoides) is one of the most versatile groundcovers for cold climates growing in both sun and shade and most soil types. Plumbago blooms in late su...

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    Hardy Plumbago (Ceratostigma) Hardy Plumbago, Leadwort Ceratostigma plumbaginoides
    As low as $8.79 Sale $8.35
    Per Plant - 2.5" Pot
    Hardy Plumbago (Ceratostigma plumbaginoides) is one of the most versatile groundcovers for cold climates growing in both sun and shade and most soil types. Plumbago blooms in late summer with deep blue flowers followed by the foliage that turns burgundy red in fall.
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  2. Nepeta faassenii Select Blue

    Nepeta 'Select Blue' (Select Blue Catmint) is a fantastic xeric perennial with dramatic lavender-blue flowers and handsome gray-green foliage. A recurrent bloomer, the first flush of...

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    Select Blue Nepeta Select Blue Catmint Nepeta faassenii Select Blue
    As low as $9.99 Sale $9.49
    Per Plant - 2.5" Pot
    Nepeta 'Select Blue' (Select Blue Catmint) is a fantastic xeric perennial with dramatic lavender-blue flowers and handsome gray-green foliage. A recurrent bloomer, the first flush of flowers comes in late spring, and again later in summer. A long-lived, easily grown perennial, this is an excellent plant for beginners.
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  3. Vic Bruno's Albuquerque Thyme Lawn

    1" tall x 18" wide. Pink Chintz Thyme (Thymus Pink Chintz) is a tight, low growing creeping thyme with thick stems of woolly green foliage that blooms in mid-spring with a profusion ...

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    Pink Chintz Creeping Thyme Pink Chintz Creeping Thyme Thymus serpyllum Pink Chintz
    As low as $7.99 Sale $7.59
    Per Plant - 2.5" Pot
    1" tall x 18" wide. Pink Chintz Thyme (Thymus Pink Chintz) is a tight, low growing creeping thyme with thick stems of woolly green foliage that blooms in mid-spring with a profusion of salmon-pink flowers.
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  4. Perovskia atriplicifolia Blue Spires

    Perovskia atriplicifolia Blue Spires (Blue Spires Russian Sage) is the best large growing Russian Sage selection blooming with dark blue flower spikes appearing in mid-summer. Though...

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    Blue Spires Russian Sage Blue Spires Russian Sage Perovskia atriplicifolia Blue Spires
    Sale Price I Save 5%
    $10.99 Sale $10.44
    Per Plant - 5" Deep Pot
    Perovskia atriplicifolia Blue Spires (Blue Spires Russian Sage) is the best large growing Russian Sage selection blooming with dark blue flower spikes appearing in mid-summer. Thought to be a hybrid of two species, this plant has amazing vigor and blooms for many months.
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