Tropical ferns to grow indoors

Flower & Garden Magazine, August-Sept, 1995 by Margaret A. Haapoja

The beauty of ferns was never more apparent than at a recent wedding I attended where Boston ferns trimmed with white ribbons were prominently displayed at the front of the church. The simple elegance of the flowing fronds more than compensated for the absence of flowers. Ferns gave the room a peaceful air and a friendly feeling, as they do in any room of the house.

Fern inhabit an unusual place in the plant world. These flowerless plants don't produce seeds for propagation. Instead, they reproduce by means of spores, which are carried by the million on some, but not all, of their fronds. Ferns require two distinct generations to complete their reproductive cycle. Many ferns are epiphytes; their roots reach into rotting vegetation in tree crevices.

Ferns come in dozens of shapes and sizes, from the small dwarf lady fern, Athyrium filix-femina `Minutissimum,' to the large maidenhair fern, Adiantum pedatum. Various types grouped together in entryways, lobbies, offices, patios or family rooms create a lush, green arrangement. Ferns also work well displayed alone or in hanging baskets.

FERNS FOR THE HOUSE

Consider ferns with glossy, hard-textured leaves. Generally, these are more tolerant of the low humidity in homes with forced-air furnaces.

Boston ferns (Nephrolepis exaltata `Bostoniensis') made their American debut in 1894, but the history of ferns long precedes that date. The ferns' 400-million-year history ranks them among the oldest plants on Earth, predated only by algae and mosses. Some 300 million years ago, they were the dominant life form, often reaching 100 feet in height. Today, only about 100 of the world's 10,000 species of ferns grow in North America's eastern deciduous forests. More ferns are found in the rain forests of humid tropical climates than anywhere else.

Despite the many species available, Boston ferns have long been an American favorite. No Victorian-era parlor was complete without one. Native to Florida and south through Central America, the Boston fern's ancestors, the wild sword ferns, are epiphytic plants with long, pendulous leaves. Boston ferns now come in more than 40 cultivars including the dwarf Boston fern `Compacta,' the giant `Bostoniensis,' the majestic `Hillsii' with forked and ruffled leaflets and `Whitmanii,' also known as the feather fern or lace fern.

Division of established plants is the simplest method for propagating Boston ferns. The divisions can consist of single-crowned offsets or of several crowns clustered together. Adding a generous pinch of bone meal to the potting mixture when repotting the divisions encourages the plants' success.

All Boston ferns are relatively easy to care for, but keep them away from heavily trafficked areas of your home. Handling their delicate fronds often causes leaflets to fall off, creating a mess while destroying the beauty of the plant. Boston ferns thrive in a soilless potting mix, loose in texture to allow for good drainage and fortified with one-third homemade compost.

A South Pacific native, the bird's-nest fern, Asplenium nidus, also lives on trees in the wild. Not only is it seen in the rain forests, but South Pacific natives use it to decorate their homes and public parks. In my house, it is effective as a table centerpiece or as the focal point on a pedestal plant stand. A small bird's-nest fern called curly bird's-nest (A. n. crispum) is compact with deep green, pleated leaves accented with a black midrib. Each year these ferns enter a period of dormancy, and some of the outer leaves turn yellow or brown. During the plant's rest period, stop fertilizing it and diminish watering. Bird's-nest ferns are often very long-lived plants.

Staghorn ferns (Platycerium bifurcatum) curious leaves reminiscent of animal antlers, and they make good hanging houseplants. The leaves vary greatly in size and have two forms: drooping fronds, which can grow as long as 3 feet and are shaped like the horns of a stag; and sterile, flat leaves, which are shield-shaped and help hold the plant together. To grow these ferns successfully in the house, you must simulate natural growing conditions and gradually acclimate them to the indoors. Rather than growing them in pots, try planting staghorn ferns in either a wire basket or a fern fiber container, substituting sphagnum moss for potting soil. These ferns do well in typical home temperatures of 68 to 72 degrees and bright, though not glaring, light. Adequate drainage is vital because excessive moisture results in rotted roots.

The delicate, fan-shaped leaflets of maidenhair ferns, Adiantum, are pale green and shimmer above shiny black stems. Indoors the tender varieties thrive in the low light of a north or east window, and they demand high humidity; hot, dry air is a real problem for maidenhair ferns. Increase humidity for these indoor plants by installing a humidifier or setting the plant on a tray filled with pebbles and water. Dropping leaves, brownish edges and wilting indicate insufficient water, and pale or yellow fronds along with wilting are signs of overwatering.