EGARDENING                   Last modified December 12, 2006

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Xeriscaping
by Catherine Kavassalis for the Oakville Horticultural Society

 

The Greek root xer- means dry and the suffix -scape comes from the term landscape. “Landscape associates people and place. Danish landskab, German landschaft, Dutch landschap, and Old English landscipe combine two roots. “Land” means both a place and the people living there. “Skabe” and “schaffen” mean “to shape”; suffixes “-skab” and “-schaft,” as in the English “-ship,” also mean association, partnership. Still strong in Scandinavian and German languages, these original meanings have all but disappeared from English.” (Anne Whiston Spirn, The Language of Landscape)

In North America, most have lost this idea of partnership with the land. Land is simply seen as a resource to be used and shaped to taste. Unfortunately with this sense of disconnection from the land has come a loss of personal responsibility for its care. Xeriscaping is one way to reestablish a responsible relationship with the land. Put simply, xeriscaping is regionally appropriate landscaping in which gardens are designed to thrive with normal area rainfall and little or no additional water.

 In a region so rich with water, why should we bother xeriscaping?

In 2001, the average Canadian used 335 liters of water per day - significantly more than in any other country, except the United States. During the summer, water consumption doubles and more than half of all municipally treated water is used for lawns and gardens. Municipal water has to be pumped, stored, treated and transported before it reaches your garden and much of what is sprayed on our lawns and flowers is lost to evaporation and runoff. Runoff carries nutrients, sediments and often pesticides from your garden into the local water system.  Xeriscaping can save money and energy and reduce pollution. It’s just good garden practice.

To xeriscape your yard, you must first understand your local conditions: rainfall, soil, light and drainage. Next, select plants that suit those conditions or amend your soil, light and drainage to broaden your choices. When you must water, do so efficiently in early morning or late evening to reduce evaporative loss and runoff. Make effective use of mulches to help retain soil moisture, prevent erosion and reduce weeds that compete for water. Prune and fertilize prudently so as not to promote excessive growth. A well planned xeriscape should require less maintenance and look good all year long.

In Southern Ontario, we average from 65-77 mm (2.5-3.0 inches) of rain per month from April to October. Many trees, shrubs and perennials are quite satisfied with this amount of rain. Particularly, our native species need little hydration assistance. Most bulbs, like tulips, grape hyacinths and daffodils, are prefect for xeriscaping. They grow when there is plenty of moisture in the spring and go dormant during summer drought. In the hottest and driest section of my yard, along with a plentiful collection of spring flowering bulbs, I find that plants like Adam's needle (our native Yucca filamentosa), Prickly Pear Cactus (our native Opuntia humifusa) and Blue Oat Grass (Helictotrichum sempervirens from dry Eurasian mountainsides) thrive. But like most of you, I am not content with just growing the plants my fast draining sandy soil would naturally support. By adding compost and amending my soil, creating shady nooks and hillocks, I have been able broaden the range of plants that can grow. I've gone so far as to use pond liner to create wetlands and bogs - not natural, but sure fun. Grouping plants of similar water requirements limits the need to water large areas. Xeriscapes need water, but with a little thoughtful planning you can reduce your use of water significantly.

Good choices for dry sun include: Adam’s needle (Yucca filamentosa), black eyed Susan (Rudbeckia hirta), blazing star (Liatris spicata), various daisies, grasses and iris, phlox, russian sage (Perovskia atriplicifolia), sedum (Hylotelephium and Sedum spp.) and yarrow (Achillea spp.).  There are also lovely choices for dry shade. Try: baneberry (Actea rubra), barren strawberry (Waldsteinia fragarioides), barrenwort (Epimedium spp.), columbine (Aquilegia spp.), dead nettle (Lamium spp.), foam flower (Tiarella cordifolia), certain geranium, hosta, leopard's bane (Doronicum orientale), ostrich fern (Matteuchia), snakeroot (Actea racemosa), and solomon seal (Maianthemum spp.). Harlequin Gardens from Boulder Colorado provides an excellent list of low water perennials for sun and shade. In addition, I have collected a list of Plants and Shrubs for Shade with Average to Dry Soil.

Lawns are the greatest drains on our summer water supply. Most of our lawns are comprised of a combination of grasses like Kentucky blue grass (Poa pratensis), creeping red fescue (Festuca rubra), perennial wild rye (Elysmus canadensis), and spreading bentgrass (Agrostis stolonifera) with a helping of interlopers (weeds).  These species of grass require about from 13-30 mm (around 1 inch) of water a week over the course of the summer. Given our local rain fall, lawns require about 25 mm of additional water a month to stay healthy (that's 2,500 liters for 1000 m2 of lawn or 624 gallons for 1000 sq feet). We tend to water much more than this. Automatic systems often don't gauge local rainfall. In addition most sprinklers tend to disperse water too widely and rapidly so that much is lost as runoff. Most lawns can only absorb about 13 mm of water in an hour. In general, slower drip irrigation systems are much more efficient than spray types. In addition, most people over-fertilize their lawns. A fast growing lawn requires lots of water. The solution is to stop automatically adding fertilizer when the bags appear in the local hardware stores, or the local lawn company tells you its time for another application. Test your soil and see if it really needs it. For most lawns, top dressing or fertilizing once in the fall is more than sufficient. Over-fertilized and over-watered lawns are shallow rooted and tend to build up thick thatch which requires dethatching or core aeration. A healthy lawn and soil, rich with decomposers, should not develop heavy thatch. Finally, mow lawns when they reach between 7-9 cm removing about one third of the blade. Leave clippings on the lawn - this returns the nutrients to the soil and provides moisture retention. Lawns can be part of a xeriscape if cared for wisely.

If we could only get the rain to come when we wanted it. With a rain barrel you can. A typical rain barrel stores about 200 liters of water. Plenty to soak a good sized garden. (Peel Region is starting to make them available to area residents for $50 as is Toronto.) A rain barrel attaches to your downspouts and stores the rain water for when you need it. They take up little room and rainwater is great for plants.

So mulch well and enjoy your summer in the garden.

May the toads nestle in your garden and keep the slugs at bay.


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