Bellevue Waterwise Garden will convince doubters how stunning a low-water-use garden can be

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If you've feared that less water in your home garden may result in loss of beauty, take a visit to the Bellevue Waterwise Garden on Wilburton Hill. It will easily convince doubters how stunning a low-water-use garden can be.

Vibrantly colorful in spring, with shimmering yellows and purples, the Waterwise Garden demonstrates the best possibilities of sensible, sensitive Northwest gardening.

Locals need to wipe the idea of reduced-interest "xeriscape" gardening from their preconceptions.

Desert gardens of the Southwest, or gardens planned for extremely arid sections of the American Rockies and plains, exist in climates far harsher than the maritime Northwest.

Information The Waterwise Garden is on the north and west sides of the Bellevue Botanical Garden Visitor Center at 12001 Main St. in Bellevue. Open daily from dawn to dusk. Admission is free. Interested volunteers should contact Patricia Burgess, Water Resource Conservation, City of Bellevue 425-452-4127. Other public utilities also sponsor waterwise demonstrations. You can visit them in Woodinville, Everett and Tacoma. Check with your own water purveyor for the garden nearest you.

To illustrate the possibilities in this area, the Bellevue Public Utilities and the Bellevue Parks Department, as a joint project, built a waterwise demonstration garden in 1993 within the Bellevue Botanical Garden. The Waterwise Garden was designed and installed by Jil and Howard Stenn of Stenn Designs on Vashon Island.

Eight years later, the garden is a living example of what works. The mature garden can also help visitors visualize their own garden plans.

Examples can be found in both sunny and shady spots.

The garden designers were fortunate to inherit an established woodland. An "entrance" area combines part sun and part shade.

More than 200 different plants flourish here with enough variety to intrigue the most eager plant collectors. (Many more exist for this region.)

When you visit, you'll find ample free handouts, including plant lists and plot plans, and excellent signage identifying many of the prominent plants.

When designing your garden, keep the following lessons from the Waterwise Garden in mind:

• Plan for year-round enjoyment. During winter, visitors experience the elegant scents of Daphne odora and Sarcococca ruscifolia, evergreen shrubs with small but pungent flowers.

Fall brings brilliant color from trees and shrubs: Amelanchier canadensis `Autumn Brilliance' and shrubby smoke bush, Cotinus coggygria.

The woodland garden glows with shrubs and grasses in yellows and bronze, with accent color from vivid-yellow and deep-purple tulips.

• Select plants for lush, intriguing foliage and branch texture. Most people wouldn't associate the word "lush" with waterwise gardening. Here, mature shrubs and perennials weave texture from the slender accents of sedges (Carex buchananii) to the overhead canopy of pines and cedar.

At one end of the woodland garden, a magnificent old Port Orford cedar (Chamaecyparis Lawsoniana) with sculptural branches sets off the smaller plants.

• Combine shrubs, herbaceous perennials and bulbs for interest and color. If you've wondered how best to place tulips in the spring garden, consider tucking them within and behind ground covers. In the part-shade entry garden, tulip 'Queen of the Night' stands out against snowy woodrush (Luzula nivea).

For best effect, replace tulips after one season, because they don't rebloom in shade.

The following plants are some of the Stenns' favorites in the garden because of how good they look year-round: Leatherleaf sedge (Carex buchanii), tough hardy geraniums (Geranium phaeum, Geranium macrorrhizum), box honeysuckle (Lonicera nitida `Baggesen's Gold') and oak-leaf hydrangea (Hydrangea quercifolia).

• If a plant thrives, try its relatives. In the dry woodland garden, several species of barberries with varying leaf and flower color adapt to similar conditions. This dry garden includes the humorously named warty barberry (Berberis verruculosa) with yellow fragrant flowers and two cultivars of crimson barberry (Berberis thunbergii).

• Repeat plantings to create a sense of harmony. The garden's unity develops from repetition of plant types and colors, with perennials like purple-leafed heuchera and epimedium used throughout.

• Prepare efficient irrigation. Drip irrigation threads through the woodland garden, allowing water to be placed where and how it's needed, without waste. All new landscape plantings require watering during their first two years.

Now, after eight years, most of the Waterwise Garden gets water only during the hottest few weeks of summer - and many plants don't need watering at all.

The herb garden (low water use) surrounds a small vegetable garden also watered with a drip irrigation system, because any vegetables will need consistent watering. A cistern to catch rainwater was installed when the garden opened but has not yet had to be used. (We'll see what the summer of 2001 brings.)

• Choose plants with few problems. The garden is managed without pesticides, relying on the natural health and hardiness of the plants to cope with problems. Howard Stenn notes that getting the right plant in the right place reduces difficulties because about two-thirds of plant failures occur when plants don't have the right soil, light or water. These are tough as well as beautiful plants, which thrive on being organically grown.

• Plan "hardscape." This garden works in part because the arbor, seating and walks flow together well. The arbors and vines also provide shade in the hottest part of the garden on the west side of the visitors center. Permeable paths through the woods allow rainfall to penetrate and reach roots.

• Properly prepare the soil. This garden started on heavy blue clay common to many Eastside locations. Four inches of compost was piled on the surface and tilled into the clay, 6 inches deep wherever possible. Occasional mulching with compost since then has also helped conserve moisture and build the soil.

• Edit the garden. If something doesn't please you, remove it and pass it along to someone who wants it. Howard Stenn remarked that several plants, such as the Corsican hellebores (Helleborus argutifolius) grew larger than their original expectation but have settled into the design.

They tried the evergreen perennial Euphorbia amygdaloides robbiae, but ended up banning it from the garden. It spread "by root and seed" to appear where it wasn't wanted. This plant often appears on lists of useful ground covers for dry shade; plant it with caution!

Getting started

If you are just starting, the Stenns suggest beginning by making an existing garden more waterwise with mulching. (Do it now while soils are still damp; be sure to use two to three inches of organic mulch. July, August and September can be the driest months in Western Washington, often with less than 1 inch of rainfall per month.)

Then install efficient irrigation such as drip irrigation or soaker hoses.

Next, assess your plants. Observe during the summer, choose the plants you like, and plan to do the larger landscape renovation in fall when the weather is great for planting and making the changes.

Group plants according to water needs.

Move out the ones that demand too much, and redesign using plants that demand much less.

Take advantage of summer nursery plant sales to choose new, waterwise plants; group the containers and mulch around them to help retain moisture in the pots until fall planting. Settle plants where direct sun won't hit the black plastic containers.

If you do choose to install container plants, be sure to keep the rootball watered until fall rains begin.

In future dry summers, which are a fact of life in this region, your garden will do its own part to protect the Northwest environment.

Mary Robson is area horticulture agent for Washington State University/King County Cooperative Extension. She writes The Practical Gardener column every Sunday in The Seattle Times.