BACKDROP: This 1,000-square-foot, 13th-floor penthouse terrace faces north, south and west and offers breathtaking views of Guilford, Tuscany-Canterbury, Roland Park, Charles Village and the entire city.
CONCEPT: With so much space to work with, the owners combine many potted evergreen trees, perennials and annuals with wrought-iron furnishings and a fence they designed using a section salvaged from the terrace below. In keeping with the open, airy space, they prefer pots not too densely planted.
CHALLENGE: Exposed on three sides, the garden’s biggest challenge is the wind. After the pots holding the evergreens blew over and broke, Barnes replaced them with heavy concrete ones, added some new trees and rejuvenated existing ones by careful root-pruning. To keep the soil from blowing away, she pins down sheets of moss that also help to retain moisture, although stones are the best mulch for high-rise gardens, she says.
Out in nature
BACKDROP: Facing east, the 16th-floor balcony of Louise and Bert Grunwald overlooks the verdant treetops that blanket Guilford and Charles Street from Charles Village south to the Inner Harbor.
CONCEPT: The Grunwalds wanted to feel like they were out in nature when they were in their balcony garden. “They wanted it tall and not all about pretty little flowers,” explains Barnes. She designed a garden of year-round interest that includes early spring blooming Siberian weeping pea (a small tree), dwarf pines and scotch broom. She also incorporated plantings in blue and yellow that bloom in fall along with the grasses.
CHALLENGE: Although the balcony is windy, watering is the main challenge, so Barnes focused on drought-resistant plantings. Still, watering is done daily with an automatic hose connected outside that gives the plants a fiveto seven-minute drink of water.
A leafy glade
BACKDROP: Perfect for viewing late summer sunsets, RenŽe and Arnold Packer’s 15th-floor balcony garden faces west, overlooking the Johns Hopkins University campus, as well as the rose garden behind the Ambassador Apartments.
CONCEPT: “I want you to produce a leafy glade,” RenŽe told Barnes in 1999. Barnes worked in conjuction with landscape architect Jonna Lazarus, who designed the garden’s architectural elements, including teak benches, planters and trellises.
CHALLENGE: Wind. “I once had plants almost blown out of the box during a late summer storm,” says Barnes. That’s why she chose lavender ‘Dutch’ and perennial blue mist shrub, which has a deep root system with clusters of blue flowers that produce a gorgeous end-of-summer show.
Leigh Barnes’ Tips for Roof- Top Gardening
Use large containers. The greater the soil mass, the greater the success, because of better water retention and more space for roots to grow.
Use lightweight pots: fiberglass, molded plastic or composites made of stone dust and fiberglass, etc. These pots retain moisture better than clay. Weight the bottom of each with stones (cinderblocks or bricks if containers are huge) to prevent them from being blown over.
In planning a terrace garden, think how water will be brought to the plants. An outside spigot is ideal. Available are hose units that fit onto kitchen faucets, as well as a variety of lightweight watering cans. Mulch pots with stones or sheet moss or underplant with small ground cover- all will hold the soil in place.
Drainage is all-important. Be sure drainage holes are in the pots (cover the bottom with a porous material such as coffee filters, fiberglass screening, even newspaper). Many fiberglass pots do not come with holes in the bottom, so ask the garden center to drill several. Always raise pots off the terrace by at least an inch, using pot feet or shims to allow the water to escape.
Choose plants that can withstand dry, windy conditions. Perennials that will live happily in pots for years include: daylillies (‘Happy Returns’ is a lemon yellow that blooms all summer); sedum (s.‘Vera Jameson,’ s. seboldii); coral bells (‘obsidian’with spectacular dark leaves); Siberian iris; lavender ‘Dutch.’ For shady areas, consider hostas combined with ferns and impatiens for color (impatiens will seed in and bloom the following year if the soil is undisturbed). Suggested annuals are surfinia petunias; mini-wave petunias; and new strains of cascading verbenas and lantana (both cascading and upright).
Buy a pair of slip-on shoes. Leave them by the door, so you don’t drag dirt inside.