A Designer’s Tips for a Rooftop Garden

A Room With A View

By: Beth Mullins
BethMullinsHeadShot

GrowsGreen Landscape Design

http://growsgreen.com

Beth Mullins specializes in residential garden design. She graduated from University of Pennsylvania with a post-doctorate in Biochemistry and has…

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Beth Mullins of Growsgreen and homeowner Richard Hosek collaborated on the design of this rooftop garden in San Francisco. Photo: Beth Mullins.

Beth Mullins of Growsgreen and homeowner Richard Hosek collaborated on the design of this rooftop garden in San Francisco. Photo: Beth Mullins.

My dirty little secret? I love interior design as much as I do landscape design. Growing up, I remember rearranging the classroom in my mind to create spaces that I thought worked better. In my imagination I would “toss” some objects out that didn’t “go” or “paint” a wall, an exercise that allowed me to settle into the spaces I encountered. In grad school I tried to feed this “spatial-organization-beast” by studying biochemistry— a system of scaffolding and highways that keep cells organized and deliver molecules and proteins to their specific destinations. It worked for a while, but I kept feeling the pull tomacroscopic design as opposed to what I was studying in the microscope.

Enjoy your rooftop garden for morning coffee or for a quick site after dinner—even if it’s cold
Define seating areas and planting spaces with painters tape to try on different lay outs early in the design process. Photo: Beth Mullins

Define seating areas and planting spaces with painters tape to try on different lay outs early in the design process. Photo: Beth Mullins

While attraction to design  is different for each of us, we can all appreciate when a space has been transformed for the better. My love of design stems from spatial organization and how things relate in scale, the intersections of texture, and the flow of movement and activity within a space. I approach designing  a new space by creating vignettes and views from all points in a garden and place hardscaping and functional elements to support existing views, while building new views and spatial transitions within the space.

Until recently, most residential gardening in San Francisco happened in the backyard. Today, lack of space and a renewed interest in vertical gardening has urban gardeners considering new venues and reclaiming space. In the absence of traditional growing areas, techniques and structures previously associated with vegetable gardening or screening for privacy are now being put to use as a framework for an entire garden.

Preseve views you want to keep and eliminate those you don't. Photo: Beth Mullins

Preseve views you want to keep and eliminate those you don’t. Photo: Beth Mullins

Enter the rooftop garden. In many instances, you are working with a space larger than an interior room. Expansive borrowed views—trees, neighbors, sky, and cityscape—offset inflexible constraints such as available space and maneuvering around pipes and outlets for the systems in the building. Roof gardens must take into consideration soil structure, plants that can handle the wind, and, unless the roof has been engineered  or retrofitted, weight. While the technicalities are still being worked out, added to, and revamped, a slew of new inventions for fastening plants to grow on walls, roofs, and even in upside-down containers are on the market.

I work with a pared-down plant palette and simple, spatially driven designs. But simple can still be lush. Rooftop gardens are exterior rooms that connect your house directly to the sky. This is the closest I get to doing interior design—outside.


Design Tips:

•       Select plants that can handle the wind. Most grasses can withstand wind; olive trees are great in containers and  exposed conditions.

•       Source lightweight planters and shallow metal trays—found or fabricated—to support growing succulents and  accommodate weight and  height restrictions.

•      Merge  planting beds by incorporating pipes or ducting and  other existing fixtures, or build custom screening to disguise them.

•       Preserve views you want to keep and eliminate those you don’t. Create privacy with screens, moveable containers, and  furniture.

•      Locating furniture next  to walls blocks the wind and  captures the last radiating heat of the building. A heated bench provides warmth efficiently since the heat will not blow away as with most outdoor heaters. Keep blankets and  jackets handy for layering when  needed.