Last Friday, Ms. Hayes wielded a pair of 24-inch tweezers also used in heart surgery as she reached into a large oval terrarium on Ms. Rohatyn's dining table to tend a dainty crop of miniature bamboo, oxalis and selaginella.
"It's a wild organic world in there," Ms. Hayes said. Her quiver of tools, which she carries around in a plastic tube, includes surgical scissors (for pruning) and a turkey baster (for watering).
Ms. Rohatyn's house was just one stop on Ms. Hayes' weekly rounds. She also visited the East 80th Street townhouse of Aby Rosen, a collector of contemporary art who is the president of RFR Holding, a Manhattan real estate empire.
"She sells a self-contained universe," Mr. Rosen said, admiring a large domed terrarium created by Ms. Hayes that sits in the middle of his dining room table. "I have eight of them in my steam shower."