Pteridium aquilinum subsp. japonicum (common bracken, "Warabi")

Japanese name: ワラビ （蕨）
Scientific name: Pteridium aquilinum subsp. japonicum

[Overview]
A deciduous fern up to 1 m tall, found in sunny grasslands and on burned mountain sites.
It often grows in colonies, and in pastures, because livestock do not eat it, it frequently forms the dominant community.
The rhizome is covered with brown hairs and creeps long and horizontally.
The leaves, in large specimens 1 m in both length and width, are triangular-ovate, three times pinnately compound, yellowish green, and somewhat stiff.
The lowest pair of pinnae is especially large.
The pinnae are deeply divided, and the pinnules are oblong, entire, and not cut at the tip.
The sporangium clusters extend long along the pinna margins, and the leaf margin curls back to form a false indusium covering the sporangia.
The young shoots are curled into a fist shape.

[History]
It appears in the Man'yoshu.

[Uses]
The young spring shoots are eaten as a wild vegetable, but they must be thoroughly stripped of their bitterness.
It is used medicinally.
Starch obtained from the rhizome is used as food and as paste under the name "warabi flour", but because refining it takes great effort, most warabimochi (a Japanese sweet) on the market today uses starch other than warabi flour.

[Cultivation]
Propagate by division.
It prefers fertile, acidic soil that is sunny and well drained.
If the conditions suit it, it grows well even when left alone, and since it spreads by extending its rhizomes, it is better to set up a frame underground to keep it from spreading too much.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground, rainfall is sufficient.
Apply organic fertilizer in early spring and after harvesting the young shoots.
There are no particular pests or diseases.

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