Thursday, June 19, 2014

Strap Water Fern

Blechnum patersonii
This fern often attracts attention in damp rainforests as the it tends to grow on the earthen faces of path cuttings, on the uphill side of paths in our wetter local national parks along the Great Dividing Range. It also grows beside or in streams, and would do well in red soil gardens, in positions where it can have mulch, and shade for at least half the day.

I imagine it might be a particularly suitable plant for one of those fashionable "green walls" - provided it faced south or east and was shaded from the midday summer sun. It also grows well indoors and in areas with very low light levels.
Strap water fern grows better if watered in dry periods, but, like all our hardy local ferns, it tends to be prone to pests and diseases if the dampness is overdone. In nature, it tolerates the long dry periods of our climate, and even some light frosts. It doesn’t have to be a pampered pot plant or fern-house specimen.
The fronds of this rather delightful plant seem to be suffering an identity crisis. The simple strap  is the most common shape, but a single mature plant might have some straps, and some fronds with varying numbers of lobes.
The foliage (once the new pink fronds have dulled to green), is a rich, dark green.

The fertile fronds are very narrow indeed. It is common among ferns for the fertile fronds to be longer and skinnier than infertile ones, but strap water ferns carry the contrast to an exaggerated degree.


Here are two infertile fronds beside two fertile ones.

The first time I saw this plant's narrow fertile leaves, with their heavily spore-encrusted edges, I mistook them for diseased fronds! Then I examined their backs, and realised they were heavily rimmed with spores.

Grown by itself, a single plant forms a rosette.