Looking up at the gracious, swaying trees on the limestone terraces of Fifth Avenue, you wonder: How do they keep those things alive? Is someone paid just to stand out there with a hose all day?
"Unless you're prepared to water a lot -- sometimes two to three times a day -- a drip irrigation system is really the best option," says Mac Carbonell, a principal of the New York landscape design firm Verdant Gardens Design.
Irrigation systems are pretty straightforward. You can do one that will last for three to four years "for cheap," says Carbonell, who called from a terrace his company is installing with over 50 planters. "The parts cost a couple hundred bucks and can be installed in five to six hours."
If you lack the confidence to set up a timed, potentially volatile system of water, pipes, soil and trees directly above your home (coward), a professional irrigation system isn't wildly expensive. It ranges from $1,500 to $5,000, or less than the deductible on your homeowner's insurance.
"You have to understand the weight load capability of your terrace before you put something up there," Carbonell warns. "You can do damage. Trees or shrubs can weigh a couple hundred pounds or more, and things can treble their weight mass in less than three years." Earthbound homeowners with aspirations of 16th-floor Edens have been surprised that their 19th- or even 20th-century buildings weren't designed to bear the weight of a forest. An easy way to mitigate the weight of a plant is to use a fiberglass planter.
A willow tree is "the one tree you should never plant on a roof," Carbonell says. "They have incredibly aggressive root systems, and they require a lot of water. So they won't make it, and also ruin your planter."
He allows that "if someone's resourceful and gets everything themselves, they could probably do something nice for 1500 bucks." If you hire a company, things get pricey fast. Carbonell's firm charges from a couple of thousand dollars to the hundreds of thousands if the job involves construction, design and work permits.
So the next time you see tufts of foliage peeking from the edge of a rooftop, don't be too envious. Considering the time, water and cost involved, perhaps it's not so terrible to be confined to the park.
James Tarmy reports on arts and culture for Bloomberg Muse, the arts and leisure section of Bloomberg News.