Xeriscaping and Water-Wise Yards
Xeriscaping isn’t a yard full of rocks. It’s a way of designing a yard that looks good on the rain we actually get, and Lethbridge, with about 375 mm a year, wind and strong sun, is exactly the kind of place it was invented for. Here’s what it means, how to do it, and which plants have proven they can take it here.
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What the word means (and doesn’t)
Xeriscape (said “ZEER-i-scape”) was coined in 1981 by Denver Water, the water utility for Denver, Colorado, during a drought. They joined the Greek word xeros, meaning dry, to “landscape”. It’s the same root as in xerophyte, a plant adapted to dry places.
Because of how it sounds, many people hear it as “zero-scape” and picture a yard of grey rock, landscape fabric and one lonely juniper. That’s not it at all. A good xeriscape is often lusher and more colourful than a plain lawn, with grasses moving in the wind, flowers from April to October, and birds and bees all summer. The “zero” part is closer to zero wasted water.
The short version: the right plant in the right place, in soil that holds water, under mulch, watered only as much as each part of the yard really needs.
Why it suits Lethbridge
Our climate is semi-arid. Summer rain tends to come in short thunderstorms rather than steady soakers, and July and August are often hot, dry and windy. A thirsty lawn here may need more water from the hose in a summer than falls from the sky.
The native prairie around the city has never had a sprinkler. Grasses like blue grama and needle-and-thread, and flowers like blanket flower and prairie coneflower, have been thriving on this rain, wind and sun for thousands of years. A xeriscape borrows their secrets.
There’s also the water supply itself. Lethbridge draws its water from the Oldman River, and in dry years the City has asked residents to cut back on outdoor watering. A yard that doesn’t depend on the hose doesn’t panic in a drought summer.
The seven principles
Xeriscaping is usually taught as seven principles. None of them are complicated, and you can start with any one.
- Plan and design. Sketch your yard. Mark the sunny and shady spots, the windy side, slopes, where snow drifts and where water runs off the roof. Decide which areas you actually use and need to look green, and which could be something else.
- Improve the soil. Add compost to help clay soak up and hold water. But don’t over-enrich beds for native prairie plants; many of them prefer lean, well-drained soil and get floppy in rich soil. See soil, compost and watering.
- Choose suitable plants. Pick plants that are hardy in zone 4 or colder and that tolerate drought, wind and alkaline soil. Native prairie plants are a great start.
- Keep lawn where it’s useful. Grass is great for kids, dogs and a game of catch. It’s less useful on a steep boulevard or a strip beside the driveway.
- Water efficiently. Group plants by water need, use drip lines or soaker hoses in beds, and water deeply and infrequently.
- Mulch. A thick layer of mulch on every bed keeps moisture in, keeps weeds down and stops wind from drying the soil.
- Maintain it sensibly. Water new plants faithfully for the first year or two until they’re established, then wean them off. Weed early, mow high, and don’t fertilize more than plants need.
Grouping plants by water need
The single most useful idea in xeriscaping is the hydrozone: putting plants with similar water needs together so you can water each group the right amount. Plant a thirsty hydrangea next to a drought-loving sage and one of them will always be unhappy.
| Zone | Where | Water | What goes there |
|---|---|---|---|
| High | Close to the house, near the tap, where you see it most | Regular watering in dry spells | Vegetable garden, containers, a small lawn, annual flowers |
| Moderate | The middle of the yard | A deep soak every week or two in hot, dry weather | Perennial borders, fruit shrubs, ornamental trees |
| Low | Far corners, slopes, boulevards, the hot south and west sides | Natural rain once established, a deep soak in a long drought | Native grasses and wildflowers, sagebrush, junipers, sedums |
Use what nature gives you. The bottom of a downspout or the low end of a slope collects runoff, so it can hold plants that like a little more water. The top of a slope and the strip along a south-facing wall dry out fastest, so they suit the toughest plants.
Lawns: smaller, smarter, or gone
Nobody has to give up their lawn. But most lawns in Lethbridge get more water than they need, and in the wrong way. Here’s how to keep grass healthy on less.
Water-wise lawn care
- Mow high. Set the mower to about 7 to 8 cm. Taller grass shades its own roots and the soil, and grows deeper roots.
- Leave the clippings. They break down in days and return water and nutrients to the soil.
- Water deeply, once a week at most. About 2.5 cm, from rain and sprinkler together, early in the morning. Then let the lawn dry out before watering again. Daily light sprinkling grows shallow roots that brown out in the first hot spell.
- Aerate compacted lawns in spring or fall, so water can soak in instead of running off.
- Overseed with drought-tolerant grasses. Fine fescues use less water than a pure Kentucky bluegrass lawn and handle some shade.
Letting it go dormant
Prairie lawn grasses have a survival trick: in a long hot, dry spell, they go dormant. The blades turn tan, but the crown at the base stays alive, and the lawn greens up again when the rain returns in the fall. A dormant lawn isn’t dead; it’s resting.
If you let it go dormant, commit to it. Switching back and forth between watering and not watering is harder on grass than either one. During a long dormancy, a light soaking every few weeks helps keep the crowns alive. Keep foot traffic off dormant grass, and don’t fertilize it.
Lawn alternatives
- Native grass meadow: blue grama, junegrass and little bluestem, mixed with prairie wildflowers. Mow it once or twice a year, or not at all.
- Clover in the lawn: white clover stays green in dry weather, feeds itself by fixing nitrogen, and the bees love it.
- Ground covers for areas you don’t walk on: thyme, sedums, pussytoes, creeping juniper.
- A bed instead of a boulevard strip: narrow strips of grass along driveways and sidewalks are the hardest to water without waste. Check City of Lethbridge rules before changing a boulevard.
Plants proven tough here
These plants appear on the Oldman Watershed Council’s list of best plants for southern Alberta’s dry prairie, and many are native to the grasslands right around Lethbridge. Give any of them full sun and soil that drains well, water them through their first season, and most will need little help after that.
Wildflowers
Blanket flower (Gaillardia aristata), dotted blazing star (Liatris punctata), prairie coneflower (Ratibida columnifera), wild bergamot (Monarda fistulosa), yarrow (Achillea millefolium), three-flowered avens or prairie smoke (Geum triflorum), narrow-leaved purple coneflower (Echinacea angustifolia).
Grasses
Blue grama (Bouteloua gracilis), junegrass (Koeleria macrantha), needle-and-thread (Stipa comata), little bluestem (Schizachyrium scoparium), Idaho fescue, prairie dropseed, Indian ricegrass. Non-native but well proven: feather reed grass and blue oat grass.
Shrubs
Silver sagebrush (Artemisia cana), silver buffaloberry (Shepherdia argentea), golden currant (Ribes aureum), skunkbush sumac (Rhus trilobata), shrubby cinquefoil (Potentilla fruticosa), Rocky Mountain juniper, soapweed yucca (Yucca glauca).
Trees
Limber pine (Pinus flexilis), bur oak (Quercus macrocarpa), black chokecherry, round-leaved hawthorn. Even drought-tolerant trees need deep watering for their first few years.
Ground covers
Creeping juniper (Juniperus horizontalis), pussytoes (Antennaria), hens and chicks, stonecrops (Sedum), creeping thyme, moss phlox.
Watch out for these:
- Kinnikinnick (bearberry) is a lovely native ground cover, but it prefers sandy, slightly acidic soil and often struggles in heavy alkaline clay.
- “Wildflower” seed mixes can include plants that are regulated weeds in Alberta, such as ox-eye daisy, dame’s rocket, common baby’s breath and common tansy. Read the ingredient list, and choose mixes of named native species. See Alberta’s weed law.
- Never dig plants from the wild prairie. Native plants like prairie crocus have deep roots and rarely survive the move, and wild grassland is shrinking. Buy nursery-grown plants or grow them from seed.
Rock, mulch and living ground covers
Rock has its place in a dry garden, around cacti, yucca, sedums and alpine plants that want sharp drainage. But a yard covered in rock isn’t a xeriscape, and in our sun it brings problems of its own:
- Rock gets hot. Stones soak up sun all day and radiate heat into the evening. A large rock bed beside the house can make the yard and the walls noticeably hotter, and can scorch plants growing in it.
- Weeds still come. Wind-blown dust and seeds settle between the stones, and soon you’re weeding gravel, which is harder than weeding soil. See natural weed control.
- Rock doesn’t feed the soil. Under rock and landscape fabric, the soil slowly gets harder and more lifeless.
Organic mulches like wood chips and shredded bark stay cooler, hold moisture, feed the soil as they break down, and are easy to plant through. Wood chips are heavy enough to stay put in our wind. Living ground covers are better still: they shade the soil, cool the air around them through their leaves, and feed bees.
What it means for you: use rock as an accent or for a true dry-garden bed, and wood-chip mulch or living ground covers everywhere else. If you already have a big rock bed, plant drought-tolerant perennials and grasses into it to shade the stones.
Prairie plants have clever ways to save water. Some have silvery or fuzzy leaves that bounce sunlight away, like wearing a white T-shirt on a hot day. Some have skinny leaves that lose less water. And many grow roots that go down much deeper than the plant is tall.
Wonder: On a hot, sunny afternoon, which would feel hotter on your hand, a big rock or a patch of grass? Why?
Try this: On a sunny afternoon, quickly touch a rock, a patch of bare soil, some wood-chip mulch and the grass. Rank them from hottest to coolest. Then go look at the leaves of a sage or a juniper with a magnifying glass.
Designing for wind
In Lethbridge, wind dries a yard out almost as much as heat does. A well-placed windbreak can cut how fast soil and plants lose water.
- Slow the wind; don’t stop it. A shrub hedge or slatted fence that lets some air through shelters a longer strip behind it than a solid wall, which causes swirling gusts on the far side.
- Plant on the windward side. Our prevailing wind comes from the west and southwest, so that’s where a hedge or a row of shrubs like silver buffaloberry, golden currant or junipers does the most good.
- Use the shelter. Put your thirstier plants in the calm lee of the house, fence or hedge, and the toughest prairie plants out in the open.
- Keep it low in the open. Low, bushy plants and grasses that bend with the wind do better on exposed sites than tall, stiff ones.
- Mulch heavily on windy sites, and choose heavier mulches like wood chips that won’t blow away.
Check the wind direction on the forecast page over a few weeks and you’ll see the west and southwest pattern for yourself. Read more about our wind, sun and dry air in our growing conditions.
Sources
- Denver Water, “Xeriscape” (origin of the word, 1981).
- Colorado water utilities’ xeriscape guides (the seven principles: planning and design, soil improvement, plant selection, practical turf areas, efficient irrigation, mulch, maintenance).
- Oldman Watershed Council, Prairie Urban Garden project, “50 Best Plants” list for southern Alberta (2024).
- Government of Alberta, Provincially regulated weeds (noxious weed list).
- City of Lethbridge, Water conservation page.
- Environment and Climate Change Canada, Canadian Climate Normals 1991–2020, Lethbridge Airport (precipitation, sunshine, wind days).