Hard Shield Fern
Polystichum aculeatum

Family: Dryopteridaceae

What it is like

Polystichum aculeatum is an evergreen Fern growing to 0.8 m (2ft 7in) by 0.5 m (1ft 8in). See above for USDA hardiness. It is hardy to UK zone 5. It is in leaf all year, and the seeds ripen from July to August. Suitable for: light (sandy) and medium (loamy) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers moist soil.

Height (m): 0.8

Where it is found

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

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

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 1

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

Medicine

Rating: 0

Other

Rating:

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

Ground cover: Ground Cover

How it is grown

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.

Propagating it: 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.

Best place to grow: Woodland Garden Dappled Shade; Shady Edge; not Deep Shade; Ground Cover;

Habit: Fern

Hardiness: 4-8

Growth:

Soil: Light (sandy), medium

Shade: Full shade, semi-shade

Moisture: Moist

Things to keep in mind

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.

Its other names

Local names

Synonyms

P. lobatum. Aspidium aculeatum.