Polystichum tsus-simense - Korean Rock Fern

Polystichum tsus-simense is a magnificent fern with small dimensions, with rather slow growth, that is very decorative all year round. Its elegant evergreen fronds, which are glossy and dark green, veined with black, contrast beautifully with the new light green shoots. This remarkable fern should be planted in partial shade in a moist and fertile, well-drained soil, where it will work wonders in a shady rockery!

This terrestrial fern, commonly known as Korean Rock Fern, belongs to the Dryopteridaceae family. It is native to eastern Asia. It can be found in China, Korea, Japan and Thailand, on slopes or rocky areas in forests, most often near watercourses. This small and very decorative fern forms a compact, spreading and arching clump. The upright rhizome is short and straight, covered with dark brown to black scales, which contrast beautifully with the dark green colour of its fronds (leaves). These are evergreen, glossy, bipinnate, narrowly lanceolate, dark green veined with black, and measure 20 to 40 cm (8 to 16 in) in length. The pinnae (leaflets) are narrow, oval and rectangular, with spiny teeth and finely pointed. The new croziers are slightly tinged with purple. This fern is a species with small development, measuring 40 cm (16 in) in all directions. With rather slow growth, this Korean Rock Fern has a long lifespan.

This variety received the Award of Garden Merit from the Royal Horticultural Society in 1997. Its name, "tsu-simense", refers to Tsushima Island, or Tsu, which is part of the Japanese archipelago.

This elegant small fern is almost of a dwarf size, and is perfect for small spaces. Hardy and requiring very little care, it should be planted in a cool to moist, humus-bearing, well-drained, neutral to acidic soil. It can be used as a standalone specimen, in groups, at the edge of a water feature, or along the edge of undergrowth. It will ideally be placed in a shaded rockery.

It will be the perfect companion for small undergrowth perennial plants, such as Wood Anemones, Lily Turfs, certain Hostas, Mondo Grasses, Japanese Rushes, Masterworts, Heucheras, Foamflowers, Saxifrages, and Solomon's Seals; as well as small bulbs such as Snowdrops, Snowflakes, Cyclamens, and Dog's Tooth Violets; or even small grasses like Japanese Rushes and Japanese Forest Grasses.

This dwarf fern is fully adapted to terrarium cultivation. It also works very well in pot cultivation on a terrace or balcony, provided that a shaded location is chosen and the substrate's humidity is monitored. It can be brought indoors in winter to enjoy it in the house. Inside, make sure to place it in light, but without direct sunlight.