Platyceriums

MANILA, Philippines - The Platycerium is a small group of large-sized ferns that are used in tropical landscapes. They are commonly known as Staghorn Ferns or Elkhorn Ferns because of the bizarre-looking fertile fronds sticking out like antlers.  

The genus is consists of 15 to 18 species (depending on the taxonomist classifying them) growing on the equatorial areas around the world. The Philippines is endowed with 2 species, namely: Platycerium grande and Platycerium coronarium. Platycerium grande is endemic to Mindanao while Platycerium coronarium is more widespread extending its domain from the Luzon through Malaysia and Indonesia to Thailand.

Platycerium coronarium

Platycerium coronariums are bright green and have shield fronds that are lobed at the top. The fertile fronds are deeply divided in a bifurcate manner and may hang 1 to 3 meters. The spore-carrying body is shaped like a kidney or an ear which distinguishes it from the other Platyceriums.

There are several biotypes of Platycerium coronarium. Philippine Platycerium coronarium strains specifically the ones from Catanduanes have shorter fertile fronds (giving a dressier look) making them more desirable in horticulture and is sought after by collectors allover the world.

Malaysian and Thai Platy-cerium coronariums have longer more spaced out bifurcation giving it a “hanging ribbons” look. The ribbon-like fronds look like a dangling mess of fronds while the Mainland Luzon stains have fertile fronds jutting out at a good angle spacing out the shorter bifurcated fertile fronds. Mainland Luzon P. coronariums are common in Metro Manila landscapes.

In the Philippines, Platycerium is reported only in Mainland Luzon and Catanduanes. Recently, Dr. Julie Barcelona collected from Bohol the last of the Bohol Platy-cerium coronariums. Only one individual was found. It was taken out of the forest when there was a still forest in Bohol. The Bohol strain is now being propagated through spores in a laboratory in Que-zon City. The plants should be ready for reintroduction in Bohol next year.

Cretin (dwarf) races of Platycerium coronariums has been created through gamma irradiation of the Catandua-nes strain. The cretins were grown for 4 years and measures less than 1 foot across while the controls (not irradiated individuals) reached 1.5 to 2 feet across after the same time. The gamma irradiation caused the fronds to curl also making the fertile fronds look bulkier. The first batch of irradiated Platycerium coronarium were sold as Platycerium coronarium “Little Annie” This strain is being re-made due to foreign demands. 

Platycerium grande

Platycerium grande is one of the most beautiful and easy to grow Platyceriums. The shield fronds are grayish-green and closely embracing with deep lobes at the apex. Bright green fertile fronds are deeply divided with large central spore patch and may hang 3 meters.

Platycerium grande are best planted high up the tree to show its magnificence when they are more mature. The common mistake of gardeners is to plant them at eye level. After 2 years of cultivation, the plant will send out fronds touching the ground.

Conservation efforts for Platycerium grande is being done by the Philippine Horticultural Society - Fern Study Group headed by Wendy Regalado. 

Platyceriums are ecologically important component of the forest ecosystems in that some plants are totally dependent on them for survival. Plants like Ophioglossum pendulum and epiphytic Hedychiums need the root system of the Platyceriums to grow and prosper. Dead Platycerium plants are the host to a broad spectrum of epiphytes and animals.

Platycerium Culture

Platyceriums are usually found along windtunnels. The space between 2 mountains with wind blowing from a lake or river is usually where they are found in nature. They grow in some of the wettest spots in the tropics but require wind movement. Growing them in stagnant air result in sickly plants.  

Being true epiphytes, it is best to mount the plant in a flat piece of wood or directly onto the bark of a strong branch of the trees but it can tolerate cement walls just as well. In Thailand, plants are mounted on fiberglass boards. The Platycerium will eventually envelope the material it is attached to. 

The top portion of Southeast Asian Platyceriums, in which P. coronarium and P. grande belongs to, are usually open with the basal or shield fronds forming a catch basin for rain and falling leaves. The decomposing leaves and twigs supplies the essential nutrients to the plant. 

The plant is not used to strong fertilizers and will burn the sides of both shield and fertile fronds. Slow release fertilizers (preferably with chelated trace elements) may be applied provided the gardener waters the Platycerium at least 2 times at 30 minute interval after application of slow release fertilizers to prevent Nitrogen loading damage. 

The safest option in fertilizing is to throw Banana peels regularly into the open shield fronds of the Platyceriums. As the banana peel decomposes, the roots of the Platycerium absorb the released nutrients. 

The most common affliction of cultivated Platyceriums is the place where it is growing is too wet but lacks air movement. These sets of conditions are responsible for the fungal and bacterial rots which manifests as round brown lesions. Weekly spray of Benomyl or Carbendazim will help the fungal infection but transferring the plant to a more favorable location is the best option.

Another deadly condition is when soil from hanging baskets splatter into the fronds. This is the most common way of getting the foliar nematodes. The nematodes colonize the fronds resulting in rotting of big patches of fertile and shield fronds. Plant eventually declines and dies. Nematodes may easily be controlled by applying Fura-dan granules every 2 weeks for 2 months or just before rainy season. Keep soil away from Platyceriums.