The marsilea genus includes some species of perennial aquatic ferns, originating in Europe, North America and Australia. They have thick rhizomatous roots, which anchor in the ground, spreading over the years; they produce thin stems that carry a single four-lobed leaf, very reminiscent of clover, of an intense green color, sometimes stained with yellow or brown. They can live completely emerged, on the edges of still water, partially submerged, with the leaves floating on the surface of the water, or completely submerged by water. They generally tend to be large colonies. If planted in small aquatic gardens they need to be contained often, to prevent them from becoming pests over time.
The Marsilea quadrifolia is certainly one of the most appreciated and cultivated species because of its four very beautiful petals. Like other plants of this genus, the Marsilea quadrifolia also rises 10-40 centimeters, has a reptant stem that is fixed to the ground thanks to very thin roots that can stretch even up to 1 meter. Finally, the leaves can be of two types, floating or immersed with different shapes depending on the level in which they grow.
Another variety of highly cultivated Marsilea is the Marsilea hirsuta, a plant similar to ferns that grows in marshy and wet areas and develops on the seabed in conditions of complete submersion. It can also be grown in meadows and in aquariums and ponds that give excellent results, thanks also to the low amount of light it requires.
The marsilea prefer clear, clean waters in full sun. Most species do not fear the cold, those originating in Australia cannot withstand temperatures below zero; during the winter they tend to lose the aerial part, which will return in spring from the rhizomes. To prevent our plants from suffering the cold or the frost of the winter season, a good practice is to move the plants into the home, in large containers.
They prefer soft and light, limestone-free, preferably slightly acid soils. They can be placed on the bottom of shallow lakes or calm watercourses, or on the edges; if desired they can also be cultivated in a container, remembering however to water 2-3 times a day and to shelter from the frost in winter.
In nature these ferns spread by releasing numerous spores into the water. Often these are transported by the birds in the summer-autumn season thus allowing the reproduction of the marsilea; in general the propagation occurs through the division of the rhizomes, which is practiced in autumn, or at the end of winter or at the beginning of spring. The rhizomes must be about ten centimeters long to make them root well. Once the rooting has taken place, the seedlings can be planted.
Marsilea: Pests and diseases
In general the marsilee, as often happens for most aquatic plants, do not fear the attack of pests or diseases. In any case, to avoid any problems related to the growth and development of the marsilea it is possible to perform a preventive treatment to avoid the onset of fungi and parasites. This must be done at the beginning of the winter season.