developement at the example of a dot fern
Worth knowing about ferns
Today the fern plants (Filicatae) form only the remnant of a plant group which used to be substantially richer in types, once. They belong like the club moss plants (Lycopsida) and horsetail plants (Equisetatae) to the Pteridophyta whose most important characteristic festures are the education of spores and a change of generations. Towards him stands the far bigger group of the flourishes and seed plants, the Phanaerogamae.
In terms of evolution, the fern plants are essentially older than the seed plants. Around 400 million years ago they formed with their relatives enormous forests which we today see as coal. At this time, the ferns reached up to 30 ms high. In the tropics, only, there are to this day some tree-shaped species. With us the eagle fern is approximately 2-m high and the biggest kind in Europe.
Today, there are still 56 species of the Pteridophyta found in Europe - and some are very rare.
The Structure of Ferns
Ferns and flourish plants are so-called 'higher' plants which differ from the 'low' plants, for example, mosses and mushrooms by there construcion. They consist of 3 basic organs, the root, shoot or trunk and leaf. Our open land ferns are hardy herbaceous plants which lost their leaves either in autumn or are winter-green or evergreen. They grow from a rhizom which is like most ferns more or less arising erect above the ground. Some species also form short creeping rhizoms, spread out over a single location. Few species , as for example the Ostrich fern (Matteuccia strutiopteris), can become annoyingas they grow metre long underground rhizomes, sometimes.
The leaves call frond with the fern, consisting of stipe and lamina. The ferns surprise by many different forms and colors which reach from redly, light green, dark green to yellowish green. Reproduction takes place around the spores, in contrast to the flourish plants which reproduce by seed. The spores of ferns are produced on the underside of the fronds, combined in groups within a spore case (sporangium). The sporangia stand together in groups (sori) sometimes covered with a veil (indusium). With some fern species the spores are produced at separate fronds, which often differ from the normal fronds a lot, for example with the Royal fern (Osmunda regalis), Sensitiv fern (Onoclea sensibilis) and Ostrich fern (Matteuccia strutiopteris). The spores mature mostly between July and November and are spread by the wind. With promising conditions, they develop themselves from the spores then become green thin flat growth, known prothallus, where the male and feminine genital organs are found. With enough humidity the conception takes place on the prothallus and it developes onto itself a young fern plant. A regular change finds it between a sexual generation (prothallus) and an unsexual generation (fern plant with spores). Ferns are resident in all climate zones. Particularly richly in ferns are regions with damp climate. The biggest species number is resident in the tropics. Here many of the species live as an Epiphyt.
Care and cultivation of ferns
Most ferns are woodland plants, so one can nearly guess which conditions are suitable for them. As in their natural environment most ferns prefer to be planted in the garden in a semi-shady place in moist soil rich in humus. In almost every garden shadowy places emerge over time. As planted trees grow, flowering plants planted there before look more and more puny, since the changing conditions are no longer suitable for them. The gardener wonders what to do. Nobody wants to cut down a well grown house tree just to restore the conditions preferred by the flowering plants. Well, time has come to look for alternatives: plants which can tolerate shade. Perhaps you have seen the slogan "green is a colour too", which is often used for advertising ferns. One runs out and gets some ferns. The next step is to prepare the soil. What are the cultural needs of a fern? We mentioned already that the soil should be rich in humus, if possible made of compost. If compost is not available, one can get round this by using composted bark or bark planting mix, available in most garden centres or nurseries. At first loosen the upper soil layer as deep as you can. Thereafter work in the top soil a layer of substrate which should be at least 5 cm thick.
Now everything is ready for planting. For an optimal arrangement I recommend planting three plants of each species, for larger ferns a single plant suffices. The ferns should be planted according to their size with the bigger ones in the back of the bed and the smaller ones at the front. Ground covering ferns such as Blechnum penna-marina or small species of Polystichum or Dryopteris are suitable for the front. In order to break up the structure of the bed one can for instance plant 3 plants of Dryopteris erytrosora in the middle of the bed. From spring until summer they will produce gorgeous reddish fronds which are a delight to every eye.
Now the bed is done. If the tree is huge, a soaker hose should be installed between the ferns for the hot summer months in order to provide sufficient humidity to the plant. If you like some colour in your fern bed, in autumn you may like to plant some bulbs or tubers of the spring flowering Cyclamen coum into the bed.
That's how many fern lovers arrived at their first fern bed. Some of them like myself became collectors of ferns, in search of more varieties, experimenting bit by bit also with those species more difficult to cultivate and demanding particular soil conditions and/or spots. It would go beyond the scope of this CD to describe all of them. Instead I would like to refer to the specific fern literature.
There are two very nice books describing many species and varieties as well as their cultural needs: Fern Growers Manual written by Barbara Joe Hoshizaki & Robbin C. Moran and Garden Ferns written by Martin Rickard, both issued by Timber Press, Portland Oregon.