Tiny variegation dots the small, silvery-blue, rounded leaves of Pilea glauca ‘Aquamarine’, a terrarium plant that loves high humidity and low light. Use its low-growing, densely matted, creeping pattern as a good base for other plants in your terrarium, or take it outside in warm weather for hanging pots or containers as an edger. It stays small — only 12 inches tall — making it easy to tuck in terrariums.
Name: Pilea glauca ‘Aquamarine’
Size: To 12 inches tall and wide
Interested in an air plant terrarium? Hardy only in Zones 9-11, Tillandsia stricta, or air plant, is an interesting choice for a terrarium. Stunning, funnel like blue, purple, or pink flowers top its slender, pale green leaves, making the plant a natural terrarium choice for both color and texture. Other good textural plants include ferns and mosses.
Name: Tillandsia stricta
Size: To 8 inches tall and wide
Tiny Acorus gramineus ‘Minimus Aureus’ rewards under a terrarium with grassy, striking golden foliage. “It’s amazing how little maintenance terrariums require,” Martin says. “They’re so apropos for people that work in an office cubicle. They won’t take a big chunk of time. Usually for weeks on end, I don’t water mine.” She does, however, open up her terrariums every so often to air them out, making sure there is still condensation on the glass. If there isn’t, Martin waters very lightly.
Name: Acorus gramineus ‘Minimus Aureus’
Size: To 14 inches tall and 6 inches wide
Black Mondo Grass
Black mondo grass, familiar to gardeners in Zones 6-9, sends up shoots of strappy leaves that turn from green to black, with delicate flowers appearing in spring. At maturity it reaches 15 inches tall so it works best for larger terrarium containers. Martin keeps this and other terrarium plants healthy by never misting them. She also doesn’t fertilize in order to keep the plants small. When planting terrariums, she makes sure to firmly put the plants in the soil.
Name: Ophiopogon planiscapus ‘Nigrescens’
Size: To 15 inches tall and 12 inches wide
One of the bigger terrarium-suitable plants is the graceful arching fern Asplenium bulbiferum, which can reach 2 feet tall and 4 feet wide so needs to be regularly cut back. The diffused light inside a terrarium is perfect for this plant, also known as mother fern, as well as shade lovers, including Fittonia, creeping fig, dwarf coleus, and dwarf orchids.
Name: Asplenium bulbiferum
Size: To 2 feet tall and 4 feet wide
Its lovely burgundy-red vertical stalks and flowers lend Saxifraga stolonifera the nickname strawberry begonia. While the plant rapidly matures, it only reaches a height of 8 inches. Even when the wispy flowers aren’t in bloom, the heart-shape foliage offers a two-tone pattern of green and deep red. To propagate for containers or other terrariums, simply snip off one of the runners. If well-tended, the plant will last a long time, as do many other terrarium bloomers.
Name: Saxifraga stolonifera
Size: To 8 inches tall and 6 inches wide