Blechnum

The Blechnum family extends to over 200 different species of fern and includes some hardy and easy to grow species. Blechnum ferns are well worth growing in the understory of larger tree ferns. In there native habitat Blechnum ferns are found in the forest understory and provide a blanket of foliage often punctuated with a splash of pink or red colour on new fronds.

The name Blechnum is derived from the Greek ‘blechnon’ which is an ancient name for fern.

The majority of Blechnum ferns are concentrated in the Southern hemisphere. There are a few native to the northern hemisphere including Blechnum spicant the ‘ladder fern’ or ‘deer fern’ which doesn’t form a trunk is a native species to many parts of Europe and Western North America. One interesting species that grows in the Southern hemisphere and also doesn’t form a trunk is Blechnum orientale (pictured below) this species has beautiful waxy green leaves with a tint of orange on new emerging fronds. Our Fern Files are going to focus on species which form trunks and can be loosely classed as tree ferns.

Blechnum orientale a tropical non trunk forming species


There are two types of Blechnum ferns, those that are considered dimorphic where the fertile and sterile fronds differ in shape. The fertile fronds are thinner in shape and stand erect from the crown in early summer. This is different from many other species of fern where fertile and sterile fronds are very similar. Ferns which do not have a true distinction between sterile and fertile fronds are classed as monomorphic.

The majority of the Blechnum family have simple fronds where the pinnae are only divided once. With most species, the pinnae are fairly wide with little space in between, giving the fronds the appearance of large, coarse textured leaves. In general the fronds are smaller in size than many other tree ferns and but often eye catching in the forest understory. Blechnum’s do not look like a typical tree fern such as Cyathea cooperi of Dicksonia antarctica but instead resemble Cycas, this is true of the likeness between Cycas revoluta and Blechnum discolor in their shuttlecock form and all round structure.

In general Blechnum’s tend to be quite hardy and the non trunk forming make excellent ground cover plants. Varieties such as Blechnum novae-zelandiae (pictured below), Blechnum penna-marina from New Zealand and British native Blechnum Spicant make excellent ground cover ferns that are resilient to frosts down to around -8°C (18°F). The trunk forming varieties tend to be less tolerant of cold and a lack of moisture and require more care than the ground cover species, but are still well worth trying in your garden or in pots and containers.

Blechnum novae-zelandiae growing alongside a stream near Taupo, New Zealand
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