Over 50 staghorn ferns, extraordinary in size, shape and variety, cast the spell of the tropics in Ann and Tony Swain's backyard-dangling from oak trees, perching on benches and lining garden paths. Several have grown to over six feet wide. "It's a relaxing hobby," Swain says, "because they are not work intensive, yet they add so much majesty and lushness to the garden."
Swain's spectacular collection began in the mid-1970s with one fern presented to him as a gift by a friend's neighbor. Learning about his newfound interest, Ann's father, who was an agricultural agent for Palm Beach County, gave the couple several more.
Indigenous to warm, humid regions near the equator, such as the Indonesian Islands, the Philippines, certain regions of coastal Africa and the island of Madagascar, these non-flowering perennials of the Polypodiaceae family belong to the genus Platycerium (from the Greek word meaning "broad horn"). Only 18 species of staghorns exist in the world (along with many varieties and hybrids); and just one species, the Platycerium andinum, is native to the Americas, specifically the Amazon-Andes mountain region of Peru and Bolivia.
Bill Coblentz, president of the Sarasota Fern Society, teaches a popular class entitled Introduction to Staghorn Ferns at Selby Gardens (his next is June 12), and shares Swain's enthusiasm for the stately, antler-fronded plants. A Sarasota native, Coblentz has been growing staghorns for over 30 years and has witnessed their increasing popularity. "In the 1950s they were practically unknown in the area," he recalls. "Then, in the '60s, people began to discover their beauty and unique, unusual and, for the most part, undemanding qualities.
"What makes them unique," he explains, "is that each plant, including those of the same variety, will produce different leaf formations." Even plants of the same species, imported from different parts of the world, look different from each other according to where they were grown. What makes them unusual is that two different fronds grow from the same plant: The "shield frond" grows at the base of the plant in an almost horizontal fashion and turns brown and crispy, as the plant matures. The "fertile fronds," which protrude from the base and extend beyond the plant's center, produce the spores necessary for reproduction.
And what makes them undemanding is their self-sufficient nature. Staghorn ferns grow best in temperatures of 60 to 70 degrees Fahrenheit or higher and thrive on humidity and filtered light. Only the common Platycerium bifurcatum will tolerate a temperature of 40 F or less for a short period. They need only regular feeding with a balanced liquid fertilizer-monthly during warm months and every other month when growth slows down- and, from time to time, banana peels, a great source of potassium.
Staghorns can be divided into two groups by the way they reproduce: those that send out "pups," or baby plants, that grow from the root system, and those that reproduce via spores (brown dust-like seeds). These are the largest, with some measuring up to eight feet tall and six to eight feet across. Among the most desirable staghorns is the P. grande, which has two spore patches on the same frond.
Usually attached to a slab of pecky cypress, redwood or a piece of hapu-grown from the roots of the Hawaiian tree fern-staghorn ferns can also be grown in hanging baskets. Due to their epiphytic (non-parasitic) habit, they require an organic, loose, well-drained potting medium such as sphagnum moss alone or mixed with other materials like tree fern fiber and leaf mold. This assures a support system and air circulation, while rain provides plenty of moisture and the necessary nutrients by washing the material off the branches and transporting it to the root area.
"Staghorns are ideally suited to local humid growing conditions and will grow beautifully, albeit slowly, provided they are protected from the intense summer sun and freezing temperatures in the winter," advises Coblentz.