Genus that counts some species of ferns, widespread in all the temperate zones of the northern hemisphere. The most commonly used as a garden plant is the Onoclea sensibilis, native to North America; these ferns produce large tufts of fronds, which develop directly from the fleshy rhizome; the fronds are light green, deeply pinnate, and sometimes even serrated; the young fronds are often covered with a thin whitish or pinkish hair. With the arrival of cold they turn yellow, and in winter the plant completely loses the aerial part; it is advisable not to remove the dry fronds until spring, since they act as a shelter against the winter colds.
The Onoclea sensibilis should be planted in a shady or partially shaded place; generally these ferns, being rustic plants, can withstand short periods of insolation, better during the cooler hours of the day, even if they can resist even the direct rays of the sun.
They do not fear the cold, and the rhizomes can withstand even very cold temperatures, even up to -15, -20 ° C.
Onoclea sensibilis plants love moist soils but can also develop in dry soil conditions. They do not like stagnant water, which can cause the roots to rot and cause the plant to die. During the spring and summer period it is advisable to supply more water, always taking care to check that the soil is not soaked with water. During the winter they do not need watering, you can proceed by wetting the base around the plant when the soil is very dry and compact.
Since the Onoclea sensibilis is a hardy and resistant plant it can adapt to different types of soil, without particular problems as regards its development.
Naturally it will develop in a greater way if placed in a slightly acid soil, rich in humus and able to maintain humidity for a long time.
It is possible to use peat, mixed with loam of leaves and a few finely chopped barks.
As for the multiplication of Onoclea sensibilis plants, in autumn it is possible to divide the fleshy rhizomes; once you get new portions, they should be immediately placed individually.
In the case in which the central fronds of the plants produce spores, it is possible to collect them in the summer: they are placed for a few days in a paper bag, to be hung in a dry place; the spores will remain in the bag already mature, which can be sown on soft soil, to be kept moist until complete spore germination.
Onoclea sensibilis: Pests and diseases
Generally, since these plants are a very resistant and rustic variety, they do not particularly fear the attack of pests or diseases.
It is possible to perform treatments with specific sulfur-based products to counteract the onset of fungal diseases.
If aphids are detected, it is possible to rely on products designed specifically to combat them effectively, remembering that it is important not to use them during the flowering period so as not to compromise their development and not to disturb the work of the bees.