Blechnum discolor

The common name for this species is the ‘Crown Fern’, the native Maori name is ‘Piupiu’. The name ‘discolor’ means of two different colours and refers to contrasting greens displayed by fertile and sterile fronds. Blechnum discolor is endemic to New Zealand and can be found growing right across the North, South, Chatham and Stewart Islands, sometimes becoming the dominant vegetation on the forest floor. The species can be found growing in many of the forest types New Zealand has, it is abundant in the forests of the Northern Island around Lake Taupo.

Blechnum disolor dominating a forest floor in New Zealand

Blechnum Discolor has bright green, upright fronds up to 1m (3ft) long which form a crown shape. With age, a short trunk of 15-20cm (6″) can form and a colony soon starts to establish around the mature plants. The species is dimorphic with long erect fertile fronds emerging from the centre of the plants crown in spring. The fertile fronds start off a light green colour with a very slight orange tinge to the tips and then turn to a dark brown as the spores ripen, as can be seen in the picture below. The fertile fronds can be produced in numbers right throughout the spring and into the late summer months. The elegant vase shaped array of erect sterile fronds forms the iconic shape of the ‘crown’ which is where the name the common name Crown Fern was derived from.

Crown Fern, Blechnum disolor with fertile frond emerging

Blechnum Discolor can be considered hardy to around -6°C (21°F) and will thrive in a semi shaded spot with a good supply of moisture. I have had best success growing this species in ericaceous compost with added leaf mulch giving at a high nutrient and free draining soil. This is another good Blechnum to try and not as fussy as many other tree ferns.

Piupiu, the Crown Fern of the New Zealand forest floor