BLECHNUM (Blech’num). Handsome ferns which are found wild in Brazil, the West Indies and other warm and temperate countries. Some kinds are of dwarf tufted growth while others, which grow about 4 ft. high, are Tree Ferns.
Those from subtropical climates need a minimum greenhouse temperature of 50 degrees; those from tropical countries must be grown in a greenhouse having a minimum temperature of about 60 degrees. There are also several hardy species. Blechnum belongs to the family Polypodiaceae. The name is derived from the Greek blechnon, a Fern.
Hints on Management. Repotting is done in February or March, or as soon as new fronds begin to unfold. The pots must be well drained: a suitable compost consists of equal parts of turfy loam, leaf mold and peat with the addition of coarse sand and small pieces of charcoal. These ferns require a shaded position and a moist atmosphere, but the fronds must not be wet. The plants should be watered freely in summer. Less water is required in winter, but the soil must not be allowed to become really dry. Some of the smaller kinds are excellent for growing in fern cases, or on rockwork in a conservatory.
Propagation by Spores. Spores are sown as soon as they are ripe on the surface of sterilized soil, in pots covered with glass and placed in saucers of water until the young plants appear. These are then transplanted at 1 in. apart, in flower pans filled with finely sifted compost, and later on, are potted separately in 2-in. pots and finally in larger pots.
The chief kinds are Blechnum occidentale, 21/2 ft., tropical America, which needs a minimum temperature of 60 degrees; B. brasiliense, 3 ft., Brazil; B. fluviatile, drooping fronds, good for hanging baskets, Australia; B. gibbum a New Caledonia kind with trunks 5 ft. tall, and B. serrulatum, 1-2 ft., Florida to Brazil, which can be grown in a greenhouse with a minimum temperature of 50 degrees.
Blechnum spicant is the Hard Fern (Deer Fern), widely distributed throughout the northern hemisphere, including North America. There are numerous crested and other varieties, all excellent for moist shady positions in the rock garden, in open woodland, or elsewhere, in loamy soil containing plenty of leaf mold or peat. Other attractive hardy kinds are B. durum, from the Chatham Islands; and, for mild climates, B. parvifolium and B. penna-marina.