Thelypteris palustris marsh fern

Marsh fern is one of the original fern species typical for Czech flora, but its quantity and occurrence has decreased so much in recent decades that it was put on the list of endangered species. Surprisingly, being a very hardy plant, its home is not only in northern countries (the northern shores of continental Europe and Scandinavia, a wide strip from Central Europe through the Caucasus to Central Asia, North America), but also hot areas around the Mediterranean Sea and the mild subtropics of Great Britain, India and southern China.

It forms 30-100 cm long fronds of light green, soft, velvety, and matte, compound, deciduous leaves. The individual leaflets (pinnae) are either rounded at the tip or more or less acuminate (pointed). They are most often arranged opposite, but sometimes alternate, and even grown together at the tip of the midrib. The stems are thin and may be slightly curved.

Due to the wide area of distribution, one would expect its variability, at least from one continent to another, but it is not the case here. Perhaps the only significant difference could lie in the length of the fronds and the style how the individual leaflets are separated from each other - most often they are attached closer to the midrib, but rarely they are conspicuously separated, yet not far apart, with their margins slightly overlapping.

You will almost never find it growing as a single clump like many terrestrial ferns, which usually have a single heart that slowly expands and from which new fronds grow. Marsh fern is a sort of a wanderer whose leaves grow directly from the ground just where they want to and, due to short runners, over time they can create a beautiful fern field if you give it space.

The name itself - marsh fern suggests that it is not a plant for a dry rockery. In the wild, it occupies moist places and marshes, or even shallow pond banks. In the garden, however, it doesn't need to stand in water all the time if you water it often, but you can also use it in garden ponds, of course, and in places where other plants would not grow because the ground often gets waterlogged. It prefers acidic soil and likes nutrients, so fertilize it annually if your soil is poor. It can take full sun, part shade or even shady location. It is very hardy and tolerates temperatures down to -34 °C (USDA zone 4).

Last update: 08-08-2024