In addition to succulents, you can try growing herbs, vegetables, trailing varieties like philodendron, native perennials (plants or flowers that are naturally grown in certain regions), and ferns, suggests Janice Goodman, President of Cityscapes Inc. in Boston. You’ll want to be aware of the “flexibility” of these plants since you’re growing them vertically. “I would be inclined to try herbaceous plants more so than woody ones, because the herbaceous kind are a little more flexible in the way they fall,” says Sullivan. Woody varietals—like trees, shrubs, or vines—have rigid, wooden stems, so they’ll grow parallel to the floor and stick out instead of flowing down. On the other hand, herbaceous plants, like flowers and ferns, have soft, green stems, so they’ll “droop” down.