On a recent chilly Wednesday, Lori Bloomberg, a horticultural therapist with NYU Langone ’s Rusk Rehabilitation center in Manhattan, pushed a cart filled with bright green foliage down the hospital’s hallways, past a row of wheelchairs and into the room of two patients, who were sitting propped up in their beds.

Today’s activity: arranging bamboo stalks in a vase. “How often do these get watered?” asked Rita Belfiore, one of the patients and a former paralegal from Brooklyn, who was recovering from hip replacement surgery.

“It’s not like watering a plant. It’s a little less intensive,” Ms. Bloomberg said. “These things drink pretty slowly.”

Ms. Belfiore and her roommate , Carol — a food broker from Massapequa, N.Y., who was recovering from spinal surgery, and who declined to give her last name — carefully wrapped rubber bands around their bamboo clusters, grazing the light brown roots that puffed out of each stalk. They filled glass vases with tiny red stones, then added water and the plants.