Up on the roof

Only one summer old, this lush Seattle roof garden is well on its way to becoming this family’s favorite close-to-home hideout. Though most homeowners’ getaways would more likely be a cantilevered deck or a patio, this rooftop provides lots of lessons in container gardening.

Four things made it come together quickly and easily: large containers, 60-pound bags of potting mix, the availability of water – piping and an outdoor spigot were installed – and an enthusiastic owner.

He makes daily rounds, watering and snipping off faded blooms and damaged foliage. When winter sets in, he’ll cut back the garden, remove a few inches of topsoil from pots, and replace it with fresh mix. He’s hoping that the big plants will stay happy for a decade.

A GARDEN ON A DECK

Get creative with containers. The rooftop garden uses big glazed pots, imported from China and Vietnam, chosen for their size and bright colors. High-fired and glazed, these pots won’t crack in winter. Be sure to fill them with a rich, sterile potting mix.

Feed and water frequently. Plant roots quickly use up the nutrients in the small amount of soil in containers, so you have to feed often (every two weeks with half-strength liquid fertilizer) and water as soon as soil starts to dry out to keep things growing.

Freely mix annuals and permanent plants. Repeat filler plants (like Bidens ferulifolia and ivy geranium) for visual continuity throughout the garden.

Don’t be afraid to try trees and shrubs in containers. The rooftop’s denizens even include a crape myrtle. Smaller pots in various shapes and sizes are filled with small shrubs and woody plants: Algerian ivy, heather, Hebe, hypericum, and others.

Use upright perennials such as gerbera, golden marguerite, and snapdragon for exclamation points of color.

Employ tender perennials and annuals, like zinnia and helichrysum, as flowery fillers.