Botanical name:

Cranfillia deltoides (Blechnum vulcanicum)

Common name(s):

Korokio, mountain hard fern

About:

This fern is native to forests from the upper North Island of New Zealand and extends southward, often exhibiting a localised distribution. It features a tufted growth habit with sterile fronds that have a unique triangular shape, reaching heights of approximately 75cm. The leaflets are somewhat leathery and a dull green in colour, with the lower pair typically curving downward. It is particularly attractive when placed on a bank, where the fronds grow almost horizontally. However, it requires a cool environment with rich, moist soil and does not thrive well in crowded conditions.

Natural habitat:

Coastal to montane. Usually in forested areas on cliff faces, rock outcrops, banks (especially roadside banks) and, less commonly on boulders and rocks along stream beds and in open forest.

Growing environment:

Shade, Wind, Coastal & Free draining tolerant.

Endemic distribution:

New Zealand’s North, South, Stewart and Chatham Islands. Also South-eastern Australia. In New Zealand uncommon north of Auckland.

Height: 75cm

Flowering: N/A Spore producing

Fruiting: N/A

Uses:

Riparian plantings & Forests

How to grow:

Often fickle. Does better in cooler climates, preferring a shaded site panted in damp, rich, free draining soil. Dislikes competition.