Sean and Emily love plants: Sean's house is covered in them (thanks quite a bit to Emily), and they plant and tend a garden together every year. And that gave Sean an idea. He chose a plant from his parents' house that he wanted to bring back to Lancaster and repot with Emily, but unbeknownst to Emily, Sean had buried the ring box under the soil. When Emily uncovered the box while repotting the plant, Sean asked her to spend forever with him, and she obviously said "yes!"