Multilevel face-lift for a really steep lot

Sunset, Oct, 1994 by Steven R. Lorton

THE HOUSES THAT perch on the hills of many Western cities are much loved for their great views. But the steep ground around these houses makes lawns impossible and gardening a challenge. Consequently, these plots often become neglected tangles of blackberries or other obstreperous plants.

Seattle landscape designer Micheal Moshier faced the challenge of a 40 [degrees]-plus slope on a 40- by 50-foot lot. He started by stripping the slope, taking out all but one large shore pine (Pinus contorta). To control soil erosion during construction, he covered the bare ground with black plastic sheeting.

Moshier kept an existing 4-foot-high concrete retaining wall topped by a hedge of English laurel at the top of the slope. Working from there, he built a series of small wooden decks and stairs that zigzag down the slope to the house. For the stairs, he used a mix of materials for utility and visual variety: concrete at the top and bottom of the slope, where street access made it easy to pour; and in the middle of the slope, where the grade is the steepest, pressure-treated wood and steel decking anchored in concrete piers.

At the bottom of the slope, he removed soil to make a level terrace at the rear of the house, and used backfill soil to plug the gap between the slope and another 4-foot-high retaining wall. He installed a small pond at one end of the terrace.

In replanting the slope, Moshier chose plants needing little water or maintenance. English ivy and sword ferns carpet the steepest areas. Farther down the slope, dwarf cotoneasters and Rubus calycinoides cover the ground. Glacier ivy crawls downhill and spills over the retaining wall, displaying its blue-green and cream leaves.

Clumps of ornamental grasses are scattered along the slope. The big roundish leaves of hostas and the spiky foliage of irises pop up here and there where a change of texture is needed.

Closer to the terrace, Artemisia 'Powis Castle' displays its fragrant, silvery leaves. The waxy, celadon leaves of Sedum 'Autumn Joy' poke up topped by rich coral blossoms that turn a handsome nut brown in winter (the owner cuts them back in spring as new foliage starts to emerge).

The silvery gray foliage of snow-in-summer (Cerastium tomentosum) and the white woolly leaves of Helichrysum petiolatum glow in the sun and brighten the slope at dusk. Lights along the steps and around the slope illuminate the garden at night.

When one plant starts to overtake another, or grows out of bounds, the owner simply snips it back. In mid-February and early April, a complete granular fertilizer (15-15-15) is scattered over the slope. An underground sprinkler system waters the slope in summer if the weather is hot and dry.