Travelers to Hawaii often bring home a cutting of a tropical plant as a living reminder of their trip. But few have a 12-foot-tall tree to show for their efforts, as do Steve Grayson and Barbara Kriz. Fifteen years ago, the San Rafael couple bought a plumeria cutting in the airport on Maui and, after potting it, kept it near the fireplace during the cool months and in an uncovered atrium during the warm months. The plant grew modestly but produced none of its famously fragrant flowers ― until one spring day three years later.

Steve covered the atrium with a translucent material called Filon. The plumeria flourished: It required repotting twice and eventually rooted through its container. The couple has since added bromeliads, gardenia, ginger, hibiscus, other tropical plants, and a fountain to the atrium.