Garden In The Sky -- A Designer Works With A Blank Canvas, A Fabulous View And Many, Many Challenges

THE CLIENT CAME to the designer with a spectacular outdoor space. It was flat, 1,500 square feet, and nearly a perfect square in shape. Most significantly there was an unobstructed view northwest to water and mountains, with not a tree or rooftop to block the sweep of blue and boats and sunsets. Not a single overgrown shrub or tree needed removing; there was no tangle of old blackberries or weed-infested lawn. What the client offered was a blank canvas - not a flower, blade of grass or even a shred of soil in sight. This job was pure potential, with one of the best views in the city.

The catch: This garden-to-be was three floors up, on the roof of an old stone mansion on Capitol Hill. Along with unimpeded sunlight came unhindered winds; it is hard to imagine a more exposed space in which to make a garden.

Designer Emery Rhodes, owner of Emery's Garden Nursery in Lynnwood, began by consulting an engineer about how much weight the roof could bear. "The idea of a hot tub was thrown out early," he laughs. Now a wading pool is brought up and filled for the owner's young children to play in on warm days.

The mansion, remodeled and modernized by the owner, was built by Sam Hill in 1908. Hill is known for constructing the Peace Arch at the British Columbia border at Blaine and the Maryhill Museum and Stonehenge replica overlooking the Columbia River.

Rhodes found an old photo of an earlier rooftop garden, but it was just blacktop with a little deck for enjoying the view. Now, a high-ceiling, marble-floored ballroom, complete with elegant fireplace, opens onto the rooftop, calling for a garden of equal distinction. "The view demanded a beautiful garden up here," Rhodes says.

The owner wanted a safe and private space for the family to enjoy being outdoors in the middle of the city, as well as for entertaining, barbecuing, and watching the sunsets in all seasons.

Rhodes began by dividing the flat, featureless space with varying textures and levels. The flooring of the deck changes as you move across the rooftop, from pea gravel to large slate pavers.

Outside the French doors of the sun-room, blue-gray slate forms a raised patio, just the right size for a white canvas umbrella to shade a teak table and four chairs. As the trees grow they will cast their shadows, creating patterns of shade to cool paving and people on the hottest days. A cedar pergola forms an open roof across a corner of the deck built in the "L" formed by two window walls. An ornamental grape climbs out of a big blue pot, trained across the lattice strips to form a leafy ceiling with shaded sitting nook beneath.

The remaining space is divided by rectangular planters raised 30 inches high, not only to delineate space but to lift the plants so the trunks of the trees and ground covers are best appreciated. To minimize their weight, the beds have false bottoms; each holds just 20 inches of a specially mixed, lightweight composite soil. Because the soil is so porous and quick-draining, and the rooftop so exposed, each box is fitted with drip irrigation and the plants are regularly and thoroughly soaked. Pavers, stone and large plants were installed by a crane able to reach up three stories; soil and smaller plants were carried up interior stairways.

Rhodes chose plantings that would look good in all seasons despite the hardships of growing in containers in bright sun and strong winds. Plantings in the boxes are permanent - an unusual mix of trees, shrubs and perennials, softened with ground covers and small ferns. Each planter holds a layered garden complete unto itself, the composite effect being various, leafy and satisfying.

Emery's Garden Nursery is particularly known for its conifers, so it is no surprise to see Japanese black pines (Pinus thunbergii) and golden threadbranch cypress (Chamaecyparis pisifera `Aurea') anchoring the planters. As with many of the plants, the cypress was chosen because it is so adaptable and slow growing - it will eventually reach just 15 feet. Both small trees add evergreen foliage, height and eye-catching trunks as focal points when surrounded by small shrubs such as Spirea japonica `Anthony Waterer' and textural ground covers like wooly thyme and the low-growing bramble Rubus calycinoides. Other tough evergreens include Japanese holly (Ilex crenata) and hinoki cypress (Chamaecyparis obtusa).

"The permanent plantings need to take well to both restriction and to pruning," Rhodes explains.

Outside-the-box thinking was clearly involved in selecting some of the plantings for the raised beds. Unexpected choices include the broad-leaved willowy perennial Macleaya microcarpa and pale pink flowering Lavatera `Barnsley' - plants not usually chosen for containers but both thriving here. Another surprise for container culture, dark-leafed bugbane (Cimicifuga simplex `Brunette'), perfumes the deck with its white flower wands late in the summer.

Deciduous trees and shrubs add seasonal interest, with the rose-colored blooms of the native flowering currant (Ribes sanguineum) planted for spring color, and the bright trunks of coral-bark maple (Acer palmatum `Sango Kaku') glowing against winter skies. Multi-trunked vine maples add oranges and gold leaves in the autumn. Colored foliage, such as the yellow-stripes of Japanese forest grass (Hakonechloa macroa `Aureola') and the deep purple of a smoketree (Cotinus coggygria `Atropurpurea'), set off the greens of the conifers.

The subtleties of the more permanent plantings are emphasized by large pots holding seasonal flowers. Rhodes chose the simplicity and sophistication of mostly white flowers for the pots. White tree roses, white geraniums and tiny white-flowered bacopa fill terra-cotta and pale stone pots, as well as hanging baskets outside the sun-room. Even the perennials in the permanent plantings are pale, such as a soft yellow scabiosa interplanted with ferns and epimedium, surrounding a Japanese black pine. White nicotiana and white impatiens, along with hostas, fill planters beneath conifers pruned to show off a rough curve of trunk.

With the view and changing sky, little ornament was needed in this garden. A couple of large dish rocks filled with water reflect passing clouds and the line of pines and maples. Rhodes had no need to search for architectural fragments to suggest age in the garden; heavy concrete rails and a stone pediment in one corner speak eloquently of history and architecture. The owner plans to build a crow's nest one more level up, a platform in one corner reached by a ladder. There the family will be able to look down on its garden in the sky and be far above the rooftop's railing for an even more stunning view of mountains, clouds, boats and water.

Valerie Easton is a horticultural librarian and writes about plants and gardens for Pacific Northwest magazine. Her e-mail address is Photographer Jacqueline Koch lives on Whidbey Island.