This article was published in the Titirangi Tatler, May 2012

Kiwakiwa

Ferns pervade the bush of the Waitakere Ranges, demonstrating to the observer that you are in a rainforest. The obvious tree ferns impress with their slender trunks reaching into the canopy. Other lower ferns are common on road and track sides.

Perhaps the dominant one you will see along the Scenic Drive is Blechnum novae-zelandiae displaying graceful 1.5 metre long fronds in shades of green and pink. Elsewhere in the country the forest understory is frequently dominated by Blechnum discolor. Its beautiful symmetry gives it the common name ‘crown fern'. Alas, its dominance is the consequence of our foolishness in introducing deer to New Zealand. Being least palatable, it is the last plant the deer choose to eat, and in a barren forest it has ample opportunity to establish widely, creating a monoculture where there should be diversity and abundance of species. It is essential that the authorities take stronger measures to keep ever-encroaching deer out of the Waitakere Ranges or our dense semi-tropical rainforest will be forever spoilt.

Less obvious are lower growing ferns, but one that generally catches the eye and draws admiration is Blechnum fluviatile or "kiwakiwa". The sterile green fronds are held flat on the ground making a striking rosette form looking rather like a starfish. From the centre rise the brown fertile fronds which have the spore-producing capsules creating a ‘dusted' look. The two types of fronds provide seasonal contrast and texture and they are a characteristic of all Blechnum ferns.

Blechnum fluviatile likes a shady site to grow with rich humus and moist but not boggy conditions. It derives its name ‘fluviatile' from the riverside habitat it favours, where it gets slightly higher light levels than in the denser forest interior. Nowadays you will often find it on track sides, which also give the extra light it likes - but not full sun.

It is a delightful plant and every garden has a suitable spot for it.