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Common Name: Hard Shield Fern

General Information

Polystichum aculeatum is a Evergreen Fern up to 0.75 metres tall.
It is harvested from the wild for local use as a food and source of materials.

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[].
Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase[].

Botanical References

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Range

Europe, including Britain, from Scandanavia south and east to N. Africa, S.W. Asia to China, Japan.

Habitat

Deciduous woodland, often on limy soils, and sometimes on shaded limestone outcrops[]. Especially in the wetter areas of Britain[].

Properties

Edibility Rating
Habit	Evergreen Fern
Height	0.75 m
Cultivation Status	Wild

Cultivation Details

Very hardy and easily grown in light shade in any reasonable soil[]. Prefers a sandy humus-rich soil in a shady position that is moist even in winter[]. Tolerates part sun for up to 6 hours a day if the soil remains moist[]. Prefers a pH in the range 6.5 to 7.5[].
A very ornamental plant[].
Members of this genus are rarely if ever troubled by browsing deer[].
Remove old fronds from the plant in the spring because they may harbour fungal diseases[].
Some named forms have been selected for their ornamental value[].

Edible Uses

Eaten in curries[]. We have no more details, it is probably the young leaves that are used though it might be the root.

Medicinal

None known

Other Uses

Plants can be grown as a ground cover and are best placed about 60cm apart each way[].

Propagation

Spores - best sown as soon as they are ripe, though they can also be sown in the spring. Sow them on the surface of a humus-rich sterilized soil. Keep the compost moist, preferably by putting a plastic bag over the pot. Pot on small clumps of plantlets as soon as they are large enough to handle and keep humid until they are well established. Do not plant outside until the ferns are at least 2 years old and then only in a very well sheltered position.
Division. This is best done in the spring.