Common names for Blechnum fluvatile include the ‘Creek Fern’ and ‘Star Fern’, native Maori names include ‘Kiwikiwi’ and ‘Kiwakiwa’. This species can be found growing along streams and other damp forest areas right across New Zealand’s North, South, Stewart and Chatham Islands.
The species is dimorphic the sterile fronds lie almost horizontal and form a rosette or star. These fronds have almost round, dull green leaflets and can reach up to 60cms long. Mature specimens can form small trunks of up to 50cm in height. The fertile fronds are dark brown and erect.
This is a very attractive species and well worth growing as it’s a unique looking fern and something unusual to add to your collection. The plant below was growing in a fern nursery on New Zealand’s North South Island near Christchurch and although scruffy in appearance you can clearly see a short trunk has developed.
Blechnum fluvatile requires moist, shaded conditions but is very fairly easy to grow. It will tolerate a few degrees of frost but it is worth mulching or growing as a pot specimen if you experience very hard winters. The species is hardy down to around -4°C (25°F) but will not tolerate the ground freezing for extended periods of time. It is worth trying this in a sheltered position in your fernery under a larger tree fern.