MANILA, Philippines - Asplenium antiquum (incorrectly referred to in some books and internet as Asplenium antiguum with a “g” instead of “q”) first appeared in United States in 1969. Since then, it has caught the attention of plant growers in Europe. The plant originated from Japan and can tolerate the cold unheated indoors in temperate countries thus making it a good indoor plant.
It became the biggest volume of fern traded in the auction markets during the late 80’s.
Asplenium antiquum resembles Asplenium nidus (common bird’s-nest fern) but is more compact and fronds are generally narrower. The plant grows to maximum 1 meter across. The upper midrib is roundish unlike in A. nidus where it is squarish or trapezoidal, while the lower midrib is definite rounded and not keeled. Stipes are short but do not have extended lower lamina and interfoliar root masses of Asp. cymbifolium.
Cultivated Varieties in Philippines:
Asplenium antiquum ‘Mt. Yonaha’. Same as the species but segments are bigger and wider. Some individuals sports wavy margins.
Asplenium antiquum ‘Victoria’ is the plicata-form of A. antiquum. Leaf margins are ruffled and fringed. Very decorative.
Asplenium antiquum ‘Osaka’ is similar to “Victoria’ but fronds are narrower and plant more compact; This variety is always incorrectly referred to in Mindanao as Asplenium nidus cv. Osaka.
Asplenium antiquum ‘variegatum’. Green and white stripes on both sides of the lamina. Very striking in appearance because of color contrast between emerald green and white. Variety produces alternate flush of highly variegated foliage and green foliage.
Asplenium antiquum ‘furcato-variegatum’. Asplenium antiquum variegatum with uniform forking leaftips.
Cultivation
Asplenium antiquum grows best under bright diffused light. Plants may be contained in plastic or terracotta pots, half the width of the plant. Over-potting results in over-watering and eventual decline of plants. If it can be helped, keep water off the foliage especially during rainy season. The plant can tolerate drying but not damp, wet conditions. Best looking plants are grown under plastic canopies with good ventilation.
A. antiquum prefers chunky or porous media. Panned (compacted) medium results in slowing down of growth due to lack of aeration around the root system.
Fertilizers may be used to increase the growth rate of the plant and to increase the leaf size. Foliar Orchid Fertilizers may be safely used at quarter dose that recommended for Orchids.
Slow release fertilizers are successfully being employed in big greenhouses in Netherlands.
Keep weeds off Asplenium antiquum. The spongy roots of Asplenium may serve as an ideal medium for unwanted plants. The plants may overwhelm the Asplenium if allowed to stay in the same pot.
Propagation
Commercial production of Asplenium antiquum is generally through spores. Production time to marketable liner takes 2 years. Specimen sizes may be attained in 3 to 4 years from spores.
For large plants, the main stem may be split into 2 or 4 pieces then re-planted. Fully symmetric plants may be attained in 1 year time.
Commercial Production Potential
Among the different Bird’s-nest ferns, Asplenium antiquum A. musifolium and A. australasicum holds the highest potential for International Potplant Market. These three species are the only ones that can withstand near-freezing temperatures.
Other Asian species may not be as cold hardy and may not survive in an unheated interior during winter.
In terms of plant form, all the 3 species have upright fronds giving the products full form. Asplenium nidus and A. cymbifolium in contrast will give a flattened look with fronds growing laterally.
With the development of the different variegata forms: A. antiquum variegatum, A. antiquum furcato-variegatum and A. musifolium variegatum, the fern world is becoming more interesting. Gone are the days when ferns should be boringly green.
Reference: Hoshizaki, B. & Moran, R. Fern Grower’s Manual. 2001 ed. Timber Press.