SUSIE MARGLIN STARTED out with an old and established Northwest garden of rhododendrons, camellias, graceful trees and sweeping lawns on the shore of Lake Washington.

Being from California, she was all too aware of the havoc that overdevelopment and the resultant lack of habitat and water can wreak on gardens and wildlife.

With that in mind she has integrated a Mediterranean garden of drought-tolerant plantings amid the familiar evergreens; she's added a bog garden in the shady low-lying part of the yard; and a butterfly border curves through the sunny front lawn.

A series of entry pergolas along a gravel walkway define the parking area, and greet visitors to the garden. To the right of the first trellis is a planting bed with contrasting textures and colorful foliage plants. "I use groundcovers and small shrubs in such highly visible areas because they don't need constant reworking like perennial beds," says Marglin.

The bright foliage of golden barberry (Berberis thunbergii `Aurea') and the delicate pale mounds of the ornamental grass Carex albula `Frosty Curls' lend brightness to the planting, and contrast with the dark crinkled leaves of the groundcover Ajuga reptans `Metallica Crispa.' A richly colored mahogany smoke tree (Cotinus coggygria `Royal Purple') form a backdrop to the lighter colors, and an assortment of sedums and species crocus give seasonal color. The evergreen element in the planting is a Rhododendron yakushianum, which stays reasonably small, and is quite drought-tolerant once established.

In the entry beds, on the decks and throughout the garden, Marglin moves pots of perennials in and out to fill in color where needed. Large purple globes of agapanthus with silver-variegated foliage add bright flowers to the combinations of foliage plants that carry the garden all year long. Lavish use of long-blooming hardy geraniums and early and late-blooming bulbs extend the gardening season. Allium, for example, blooms in May, but its large seed heads lend a presence to the garden for many months after the color fades.

Several small trees, such as the Korean dogwood (Cornus kousa) with white flowers in summer, the golden locust (Robinia pseudoacacia `Frisia') with bright yellow foliage, and the redbud (Cercis canadensis `Forest Pansy') with burgundy heart-shaped leaves lend color and texture to the garden, and an understory to the larger evergreen trees.

In the shady border grow many moisture-loving plants that get by without supplementary water. Marglin achieves this by planting the ground so thickly that little moisture can evaporate from the soil. Hostas, pulmonaria, vinca, saxifrages, astilbe and Pacific coast iris form a lush garden around a bog amid the trees.

Across the gravel path from the shade garden, and up a rockery bright with grasses, sedums and lavender, is a large sunny drought-tolerant border. Such typical Mediterranean plants as cistus, santolinas and lamb's ears mingle with the soft apricot of the single rose `Sally Holmes.' A clump of South African honey bush (Melianthus major) with its exotic foot-long gray-green leaves, makes a striking display. The small open petals of Rosa chinensis `Mutabilis' open a bright pink and fade to orange, echoing the watermelon and sunset colors of surrounding Peruvian lilies (Alstroemeria hybrids). "I let the plants set their own pattern," says Marglin. "When it gets too hot, the Peruvian lilies go dormant, and then the plants that really like heat, such as salvia, plumbago and Russian sage, come into their own."

More unusual plants thrive in this colorful border, such as Plectranthus, with its rounded felty leaves, spiked pale blooms and lavender stems. Marglin brought this plant back from California several years ago, but it can now be found in Seattle nurseries too. Zauschneria, known as the California fuchsia, has fine-textured silver foliage with orange flowers that attract hummingbirds, and grows happily without any water besides rainfall. A large berm is covered with the large and showy Matilija poppy (Romneya coulteri), which thrives on dry soil and neglect. These brilliantly white flowers can reach nine inches across, with a mass of golden stamens and gray-toned foliage.

The border is trimmed with ornamental oreganos, some golden and others in pale green, such as `Kent Beauty,' whose blooms are described by Marglin as "looking like little reptilian heads." She uses these for flower arranging, a hobby that influences her choice of plants all through the garden.

Many of the colorful and exuberant plants Marglin has chosen are native to California or the Mediterranean, with their silver and gray foliages. "This is the kind of gardening I am comfortable with," explains Marglin. "We just can't continue to garden the way we used to."

A Master Gardener, Marglin manages her one acre of cultivated garden with only the use of slug bait. How can the garden be so lush with little or no supplementary water, no spraying, no chemical fertilizers?

"There are so many wonderful plants that are naturally disease and pest-resistant," says Marglin. As an example, she laments a beautiful native dogwood that she had removed, because it just wasn't healthy. "I won't fight it," she exclaims. "Nature gives us our best clues - if a plant isn't happy, I'll move it around or find a different plant that will do better." She also cleans up the garden thoroughly: "I'm always raking up!" This eliminates leaves that harbor diseases, and hiding places for pests. She also feeds the soil with a thick mulch of cow manure every fall, adding soil amendments to create soil that is rich but free-draining.

In keeping with using less chemicals and water, Marglin has eliminated most of the lawn. In a flat, sunny grassy area, between the house and the slope down to the beach, is a wide, curving butterfly border. Butterflies, bees and hummingbirds flock to feed from buddleia, sunflowers, Joe Pye weed (Eupatorium maculatum), sweet hesperus, filipendula and the Himalaya honeysuckle. Here she also grows colorful, smaller perennials such as astilbe, usually considered a shade plant.

"It does fine in the sun once it is established," explains Marglin. "Plants are like people; they can survive in a variety of conditions if you give them enough time to acclimate."

Valerie Easton is a horticultural librarian and writes regularly for Pacific. Gary Settle is Pacific's picture editor.