Asplenium bird’s nest fern
Approximately 600 species of this genus are distributed all over the world. In addition to species from tropical and subtropical regions that are suitable as indoor plants, representatives of this species also occur in regions with a temperate climate. They often grow in particularly exposed spots, such as on rocks or walls and are widely distributed even in alpine regions. In northern Europe the following occur naturally: Asplenium adiantum-nigrum, Asplenium rutamuraria, Asplenium septentrionale, maidenhair spleenwort (Asplenium trichomanes) and Asplenium viride.
The species in this genus demonstrate a surprisingly wide range of shapes and forms. Ferns showing two completely different shapes of growth are used as indoor plants: the bird’s nest ferns and the bulbiferous ferns. The giant bird’s nest ferns possess undivided, large leaves, while the bulbiferous ferns have multi-feathered leaves. Tiny offset plantlets form on the latter’s finely feathered fronds.
The spore capsules are generally arranged in longish groups along the lateral veins in this genus.
• Asplenium nidus, the best-known bird’s nest fern, forms large funnel-shaped rosettes with its undivided, spear-shaped leaves in which it is able to collect water and nutrients. If you have ever seen a giant specimen in a botanical garden, some of which attain a diameter of 2-3 m (7-10 ft), you will be able to imagine how these funnels are able to catch falling leaves and other organic material which then serve the fern as a source of nutrients. For this reason the bird’s nest fern is often compared to a bromeliad. The dark brown to black central veins stand out attractively against the shiny light green of the leaves. Theare formed in the upper third of mature fronds, along the lateral veins. Sometimes the variety "Fimbriatum" is offered for sale. This has clearly lobed leaves. It grows very slowly.
• Asplenium antiguum is a bird’s nest fern that has only recently appeared on the market. It is a species with narrower leaves that taper towards the tip. The leaf edges of the variety "Osaka" are wavy.
• Asplenium bulbiferum, Asplenium daucifolium and Asplenium dimorphum belong to the group of bulbiferous ferns. They possess two to multi-feathered fronds. Tiny fern plantlets are formed from bulbils in the upper sections of the leaves. The fronds become heavy and then lean down to the ground where the young plantlets take root. Asplenium dimorphum is considered to be the most resilient species of the bulbiferous ferns given here.
Origin: Asplenium nidus, an epiphyte, is at home in the tropical rainforests of Africa, Asia and Australia. Asplenium antiguum originates in Japan. Bulbiferous ferns are found growing terrestrially in Australia, New Zealand, on Norfolk Island, in northern India and on the Mascarene Islands.
Position: Bird’s nest fern semi-shady to bright; bulbiferous ferns semi-shady to shady. Room temperature should be even all year round but may drop to 16° C (61° F) during the winter. Around 12-15° C (54-59° F) may be sufficient for bulbiferous ferns in winter. The plants prefer high humidity but Asplenium nidus will cope with drier air.
Care: Bulbiferous ferns should be kept fairly moist all year round. Bird’s nest ferns require medium watering. The funnels should be sprayed often or you could mist the entire plant. Give weak doses of fertilizer fortnightly between the first month of spring and the first month of autumn. Repot in the spring if required. Do not use very large pots for bird’s nest ferns and keep the compost loose.
Propagation: Fromand plantlets.
Pests, diseases: Scale insects; brown edges to leaves are caused by too low humidity or too cool a position for Asplenium nidus.
My tip: Bird’s nest ferns are eminently suitable for epiphyte trunks and fern pillars.