Birds Nest Fern (Asplenium nidus complex), ferns of tropical and subtropical environments across the Indo-Pacific and favoured pot plants secretly yearning for freedom.
Adopted globally as an impressive ornamental fern suited to use both indoors and as a large outdoor specimen, Birds Nest Fern can be both a ground-fern and a capable epiphyte that supplements rainforest canopies in Queensland and NSW. Historically though, it was not recorded in Victoria, and has not been included in the Flora of VIctoria. Its popularity in cultivation and the ongoing exclusion of frost days from parts of Melbourne and Southern Victoria make its spontaneous establishment in the environment an increasing possibility.
In its normal range the fern colonises earth, rock, and the trunks of trees, palms and tree ferns. This provides the species with plenty of capacity to engage with urban strata where moisture is on offer. The species is also drought sensitive; research has previously found that 4-8 weeks of drought were lethal to epiphytic individuals in Queensland. In Melbourne, this will limit the fern’s capacity to become a colonist of soil or exposed structure, although as these photographs show and after several months of very dry conditions here, there is always a niche.
The photographed plant was found in East Melbourne, having colonised the unused downpipe elbow of a shop canopy. Behind the plastic filter grille, this untended elbow has filled with debris, presumably a rich organic humus built from the leaf and seed litter of nearby plane trees. The canopy roof is drained at its other end through a downpipe to sewer, but presumably not very efficiently as this fern appears very well watered. It has established approximately 150 m from a very large Birds Nest Fern in a front garden, which has spore structures visible from the footpath (see frame #7). That plant is the most likely parent, although there are probably further individuals in cultivation in Fitzroy Gardens and on various surrounding balconies.