Filmy Ferns
These constitute a distinct class, requiring different treatment from any other members of the family. Very few do well in an open house, as sufficient atmospheric moisture cannot be obtained. On the whole, they do not require much heat, being often found to grow stronger and keep in better health when cultivated in close cases, in a cool Fernery, than when placed in similar cases in the stove. Filmy Ferns should never be watered overhead, but the stones and moss amongst which they are generally grown must be kept continually moist by having water poured on from the small spout of a can. This, when evaporating inside the inclosed case, becomes condensed on the extremely numerous divisions of the fronds as represented in the majority of species, and its continued presence there invariably indicates good health and the frequency with which it will be necessary to give water. Pieces of rough fibry peat and loam, with charcoal and sphagnum, are most suitable for Filmy Ferns. Nearly all that grow in soil succeed better when planted amongst stones, while those that form rhizomes should be placed on blocks of peat, dead pieces of Tree Fern, &c. They must always be shaded from sunshine; and not much light is required at any time. The difficulty generally experienced is in establishing the plants; when once they begin to grow and increase, the treatment is, in most cases, simple enough. Hymenophyllum, Todea, and Trichomanes, are three of the principal genera among Filmy Ferns. Todea superba is a vigorous species, having large fronds of a filmy texture; and T. hymenophylloides is smaller-growing, but very desirable; both being beautiful and more easily grown than the majority of the plants in this section. WARDIAN CASES. Ferns used for decorating Wardian cases must only include those of small or moderate growth, the space inside being very limited. The system admits of more moisture being kept round the plants than would be possible in an open room where the air is frequently dried either by burning gas or a fire. It is always important, in changing plants in these cases that become unhealthy, to substitute others from a cool house, as, if insufficiently hardened, the young fronds soon wither and die. Ample drainage must be provided, and, if plants in pots are used, the latter should be covered with growing sphagnum. Ferns in Wardian cases keep fresh and attractive for a long time if they receive proper attention. Cases somewhat similar in construction, may be used in cool houses for small collections of Filmy Ferns. TREE FERNS. Considerable space and lofty houses are essential for growing and exhibiting Tree Ferns in their true characters. In Ferneries of limited size, where a few are cultivated, it is best to restrict their root growth in large pots or tubs, which also allows of their being re-arranged occasionally when overgrowing other smaller plants. In very large conservatories, a few permanent specimens planted out in well-drained borders, succeed, perhaps, better than in any other position, and always present a majestic appearance unexcelled by any other plants similarly employed. Alsophila australis and A. excelsa, Cyathea dealbata and C. medullaris (the latter is probably the tallest-growing of all our cultivated Ferns), with Dicksonia antarctica, are the best for culture in the greenhouse. All these may also be used in sub-tropical gardening outside in summer, in sheltered, shady places. There are many stove species of Tree Ferns, all of which are beautiful, and worthy of cultivation in large heated structures. They all, especially Alsophilas, delight in plenty of atmospheric moisture and shade. The stems of imported Tree Ferns should, on their arrival, be covered with damp moss or canvas, and be kept moist by syringing until the new fronds appear. The time this takes varies according to the condition in which they arrive, and the season. When the head of fronds is established, the covering may be removed from the stem; but frequent syringing in summer time is of the highest importance, as by far the greater portion of the stems of many is literally a mass of roots requiring a quantity of water. Tree Ferns, in bad health, may often be greatly improved by covering the stem from the base to the fronds with 1in. of sphagnum, and tying it on with string. If kept moist, the roots soon fill the moss, and the stem is thus considerably enlarged. Tree Ferns that are dead on arrival may be utilized by covering with epiphytal or other small Ferns for stove or greenhouse decoration the top being scooped out, and a free-growing variety with a pendent habit inserted and planted in soil; others being fastened on the side with blocks of peat and some small wire. HARDY FERNS. These are all attractive, and the majority succeed best when planted on rockwork in a shady situation, sheltered from high winds. A great diversity, both in size and habit, is represented by the British species and their innumerable varieties, apart from those introduced for North America, Japan, &c. Many suitable positions for hardy Ferns may be found in most gardens where their culture is not now attempted. They should have a good depth of soil, and plenty of water in summer. In the case of a collection, a pile of rockwork, built with rough stones, allows of a place being selected for all, according to their size and habit. A good clump of those which are plentiful should be planted together, and sufficient space allowed them to grow and develop, as in this way the different characters are much better shown than when only single plants are used. Attention in their arrangement should also be directed in placing the evergreen and deciduous species irregularly throughout the space covered, so that the whole may be, more or less, furnished at all seasons. In building a rockwork for hardy Ferns, the requirements of the plants must be the main object, large, well-drained pockets being insured in preference to the appearance of the stones, that are, in great part, hidden by the fronds. Loam and peat, with a quantity of crushed stone or brick, intermixed and used round the roots when planting, materially assist them to become established. The Royal Fern (Osmunda regalis) is one of the most handsome, and succeeds best when planted in a partial bog, or by the side of water.
UNDERGROUND FERNERY. This is an interesting structure, to be seen only in a few places, where the owners bestow special attention on Fern culture in its various aspects. It consists of a large cavity, dug in the middle of a hill, and covered with sheet glass, the hill itself being surrounded on the summit with trees. A flight of steps communicates with the interior, where Ferns are grown on the inside of the cavity in prepared soil, narrow paths or stepping stones being provided on which to walk amongst them. A fountain, or other arrangement for water, supplies the necessary moisture. The plants do not require artificial heat, as they are not much affected by fluctuations of temperature outside, and a subdued light is constantly admitted by the glass overhead. A view of an underground Fernery is shown in Fig. 7. SOIL, POTS, &c., FOR FERN CULTURE. Nearly all Ferns require a quantity of water in summer, and rarely need to be dry at the roots at any season, consequently a very important matter is that of efficient drainage. Anything like a sour or waterlogged soil is either detrimental or fatal, even to those which are not quickly injured in other respects. Success in the cultivation of established plants depends more on this, with careful watering, temperature, atmospheric moisture, proper shade, &c., than on any soil in which they may be grown. Adiantums, for instance, succeed well either in peat or loam alone, the texture of the fronds being firmer in the latter instance, and presenting apparently the only difference. A large proportion of peat was at one time considered necessary for all Ferns, but the superior qualities of leaf soil in their culture, where it can be obtained, have been more fully recognized of late, with considerable advantage to the plants. Soft sandstone, mixed with the soil, tends to keep it porous, and suits some varieties better than others; and charcoal may be used freely with all. The different habits will often suggest the mode of treatment required. It will not be far wrong to say that a compost of half loam, to which is added an equal quantity of leaf soil and peat combined, and sufficient charcoal, small pieces of crocks, or sharp sand, to keep the whole open, may be used successfully for all Tree Ferns and any established plants of Adiantum, Aspidium, Asplenium, many species of Davallia, Gymnogramme, Lomaria, Nephrodium, Pteris, and any others of similar habit. The species of Acrostichum, Devallia, &c., that form slender rhizomes, must be attached to something on which they can grow. A good plan is to cultivate in pans, placing an inverted pot or a piece of Tree Fern stem in the middle, and then building a small mound on the top with lumps of peat, loam, and sphagnum, afterwards fixing the rhizomes to the surface with small pegs. Epiphytal Ferns, of which Platycerium is a well-known and distinct genus, often succeed admirably if fastened with a little moss and peat to a block of wood, and suspended in the stove. They should be kept rather dry in winter. Similar composts, as advised above, if passed through a sieve, may be used for young plants. Ferns succeed in pots comparatively small for the size of plants, if due attention is given to watering. Small pots have also an advantage in appearance; and any deficiency in the quantity of food contained in the soil may be supplied with applications of manure water during the growing season.
Insects. Ferns, especially those under stove treatment, are liable to be attacked by several destructive insect pests. Thrips are their greatest enemies, causing irreparable damage to the fronds. Frequent fumigating becomes a necessity; this must be done lightly and with the greatest care, on account of the tender growth. Any Aphides will also be destroyed by the smoke at the same time. Brown and White Scale are sometimes plentiful, and these must be removed by sponge or brush. The first-named is the one most common on Ferns, the other, fortunately, being more rarely found, as, when once established, it is very difficult to eradicate. Mealy Bug must be destroyed in a similar way to Scale, as an insectieide strong enough to kill either, will, to say the least, be dangerous to use, in consequence of causing injury to the fronds of delicate texture. In winter, when the plants are at rest, the whole should be examined and cleaned, as stronger measures may then be adopted, by fumigation or the use of an insecticide, than would be safe after growth commences. At all times, a watch must be kept for the first appearance of insects, as proper means for destruction then applied are always more effective in their results.