Hard Water-fern

The hard water fern is found in all of the south eastern Australian states. In Tasmania, it is widespread and abundant, ranging from sea level to 1000 m, in a range of vegetation types. The species is found in many rainforests, and wet sclerophyll forests, preferring damp, shaded areas that are along creek and river beds, on the margins of water courses and waterfalls. This fern prefers a loam/sandy, well-drained soil rich in humus.

Parablechnum wattsii shows the typical life stages of a fern with distinct sporophyte and gametophyte stages. A distinctive feature of the Blechnaceae is the presence of separate fertile and sterile, photosynthetic fronds. The fertile frond produces numerous spores which are prolific and easily collected and propagated to mature plants. It takes around 4–6 weeks for the prothallus to form, and another 6–12 months for the first true fern frond to develop. Mature plants can also be divided from root stock, providing there is little disturbance to the parent rhizome. Natural division through injury of the underground rhizome may also occur as the fern ages and degradation takes place. Once propagated, P. wattsii requires moist sheltered and partially shaded conditions.

Hard water ferns are propagated for use in large ferneries, beside shaded water areas, and sheltered gullies. P. wattsii is intolerant of drying out so it should be used in areas where water availability is adequate. Aboriginal Australians also use the fern rhizomes for food, eating them raw or roasted as a source of starch.