The Value of Ferns - How to Sow Spores - Pricking Off - Propagation by Offsets and Bulbils Crown Division-rhizomatous Ferns
A collection of ferns will naturally appeal to most lovers of the garden or greenhouse. Besides their grace and lightness, their restful and beautiful colouring, and the endless varieties which can be grown, they have the practical advantage of not requiring much sunlight, many indeed flourishing best in nooks and corners where the sun hardly penetrates.
Many an ugly corner in a London garden can be turned into a beauty-spot by building a simple rockery with wide pockets of soil between the bricks or stones, and filling them with common hardy ferns, such as are seen in nooks and corners in many parts of Britain.
A greenhouse of unfortunate aspect, as well as the spaces near the floor in one of more favoured position, should also be beautified by planting ferns, and" their near allies, the selaginellas and liverworts.
The propagation of ferns may be carried out in a good many different ways, either by spores, by bulbils or offsets, by crown division, or by division of a creeping root-stock. The latter methods will each apply to different classes of ferns, while spore
Fern spores in a seed-pan. Sowing must be done as thinly as possible in a sterilised compost covered with finely sifted loam. The pan may be covered with glass, or sunk in a case of cocoa-fibre, beneath a hand-light propagation is, of course, common to them all. Although this is the lengthiest method as regards result, it is, no doubt, the most interesting to fern enthusiasts, because it possesses a pleasant element of uncertainty a possibility of securing some treasures from among batches of seedlings as these are pricked out.
Fern spores may be sown at any time of the year, but spring is the most suitable season, as this will allow of the young plants forming good crowns to carry them through the winter. When it is noticed that the spore cases or spore-bearing fronds are beginning to lift, the latter should be gathered and spread upon paper in a warm, dry place.
In two or three days the paper will be covered with a fine dust; that is, with ripened spores. In preparing to sow them, see that the pans or boxes used are very clean. Good drainage should be provided, the crocks being covered with a layer of moss or peat fibre. The compost should be the same as for ferns in a mature state, and will vary a little in composition, according to the class of fern to be propagated ; but it is best in all cases to cover the surface with a layer of very finely sifted loam. Make this even and
Sowing must be done as thinly as possible, remembering the enormous quantity of spores which each tiny pinch will disseminate. A still day should be chosen for the work. Do not cover the spores with soil, but place a sheet of glass over the seed-pan, or sink the pans in a case containing clean cocoa fibre, covering them with a hand-light. Artificial heat, except in the case of exotic ferns, is not indispensable, although it will be found a great help. See that the fern-pans are properly labelled. Shade them from strong sunshine, and keep the soil nicely moist.
In course of time, which will vary from a few days to several months, the surface of the soil will be seen to assume a greenish hue. Little scales will presently appear ; these are the prothalli, or first beginnings of fern life. A period of from two to six months from the time of sowing will elapse before the young ferns ultimately develop from these prothalli. During a state of apparent dormancy, which may continue for several weeks, the spores will assume maturity, and throughout this time great care must be taken to maintain a uniform condition of moisture.
The tiny patches of prothalli will now require to be lifted and transplanted into other pans. They should be placed an inch apart. This process will need to be repeated several times as the little plants develop. Air can be admitted by tilting the glass covers to one side, and in time removing them altogether. The appearance of strangers among the young fern plants should not occasion surprise, as fern spores of a quite distinct species or variety are often deposited on another frond, and are then sown with the rest. A sight of the first two or three fronds should determine the collector as to whether a fern is worth preserving; if it is not, she had better destroy it at once, or she may end by overcrowding the house with inferior varieties.
Damp walls or stony places within reach of water may often be made beautiful by sowing fern spores in their crevices, first filling them in with a little fresh soil. If the spores germinate freely, some thinning out will be needed in order to encourage luxuriant growth.
The bulbil of a proliferous fern, showing its method of growing on the frond of the parent plant
Bulbil of a proliferous fern, showing the root by which it will be propagated when detached
Such ferns as develop their fronds around a central core - ferns of the " shuttlecock " section - are constantly known to produce offsets from the bases of their fronds. Since it is far better policy to keep the parent fern to a single crown, detaching these young plants will serve a double purpose. They should be potted up or planted out in suitable soil, and left alone until established. Ferns which bear bulbils on the surface of their fronds, as in the well-known instance of Asplenium bulbiferum, are speedily propagated by pegging down a frond, so that the bulbils come in contact with soil.
Those which bear adventitious buds along the rachis - or portion corresponding to the mid-rib of a leaf - only, or which produce them from scales or stolons springing from the base of, a frond, should be stimulated into growth before the stalks show signs of decay, early separation from the parent plant being needful for their normal development.
Fadyena prolifera, shown in the illustration, is an example of a class of ferns which produce at the extremity of their fronds a single bulbil. It is, of course, merely necessary to remove these leafy tassels as soon as roots appear, and start them afresh in the needful temperature.
The very small bulbils which form on roots of certain species of ferns - e.g., some of the platyceriums and adiantums - cannot safely be detached from the parent fern until they have developed one or two fronds.
In propagating ferns by division of their crowns, these should be just divided slightly with a sharp knife, and then pulled gently apart, retaining to each portion as many roots as possible. If the roots are very much matted, it is better to shake or even wash them free of soil, rather than adopt such a drastic method as cutting entirely through the crown and ball.
In dealing with British ferns, it is sufficient to place the divisions, after potting up, in a cold frame, keeping them on the dry side until the first fronds have made a start. Stove and greenhouse varieties should be kept close and shaded for a few days in a case, after which they may be submitted to their accustomed temperature.
Ferns with creeping rhizomes, such as characterise certain species of poly-podium and davailia, can be propagated successfully by division of the root stock, provided that each portion possesses a growing point with a bunch of roots attached. The several portions should be pegged down firmly, and the roots well covered with soil of a very porous nature. This porosity is specially needful to prevent sourness, for plenty of water must be given to the ferns after division. They will be best kept in a close frame at the beginning, as this will encourage them to become re-established, and ready in a short time for ordinary conditions of culture.
During their sojourn in the cold frame, great care must be taken to water with extreme caution and judgment, for if too much water be given, the fatal damping-off is certain to ensue. On the other hand, if water be withheld unduly, the roots will as certainly suffer.
The temperature of the water given, too, is important. Rainwater is best, but it should not be taken from a butt early on a frosty morning, nor should water from an icy-cold well be used.
And, finally, attention must be paid to ventilation, the lights being slightly raised on warm, muggy days, but left closed in cold winds or frosty weather.
Fadyena prolifera. with bulbils and roots ready for propagating The bulbils are produced at the extremity of each frond, and should be detached as soon as the roots appear