Blechnum chilense - Chilean Hard Fern

Blechnum chilense is a beautiful South American fern with large, upright and rigid fronds, which are spectacular. They are bronze in their youth and then become bright green. Provide it with an acidic to neutral, humus-rich and moist to wet, but perfectly drained, dense or clear shade. It will thrive in a garden with an exotic and lush atmosphere, but should be reserved for mild climates.

Chilean blechnum is a fern found on riverbanks and in damp undergrowth. Recent genetic studies have classified this species in a new genus, and it is sometimes now found under the name Parablechnum cordatum. It forms dense clumps of evergreen, upright or slightly arching, tough and rigid fronds on reddish petioles. They emerge in bronze tones and then turn to a shiny bottle green on the upper side of the fronds, and light green underneath. The "leaflet" (called pinnae in ferns) are pointed, and their margin is slightly undulate. They emerge in a folded arc shape (which gives them their amusing local name of "costillas de vaca", or "cow's ribs"). In this species, the fertile fronds are quite different from the sterile fronds: their pinnae are very narrow and a fawn colour. Clumps spread through rhizomes, and very old plants sometimes form a small upright trunk. In our climates, the plant will reach about 1m (3ft) in height and 1 to 1.5m (3 to 5ft) in width under good conditions, but in its native regions, clumps can be much larger.

Given its origins, Blechnum chilense appreciates mild climates: its hardiness will not exceed -10 to -12°C (14 to 10.4°F) once established and in sheltered positions (fronds are damaged below -6°C (21.2°F)). It should be reserved for regions where winters are not too harsh, but summers are not too hot or dry either. Protect the fronds from snow, which tends to break them. This species requires an acidic or neutral soil, rich in organic matter, moist to wet, but above all well-drained, otherwise the stump may rot. An addition of leaf compost can improve your soil if it is too heavy, but avoid planting it in excessively clayey and wet soil during winter. You can overcome this obstacle by planting on a cool slope or by elevating the plant. It can also be grown in pots, with careful watering.

If your climate allows it, create a tropical garden atmosphere by associating it with tree ferns (Dicksonia, Cyathea), although other hardy ferns such as Dryopteris sieboldii or Polystichum acrostichoides can also fulfill this role more moderately. Fatsia polycarpa, Boehmeria biloba, and Arthropodium cirratum will also make wonderful companions for an exotic and graphic atmosphere!