Royal Fern, Flowering Fern

Osmunda regalis

Physical Characteristics

Osmunda regalis is a FERN growing to 2 m (6ft) by 1 m (3ft 3in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 2. The seeds ripen from June to August. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.

Distribution

Europe, including Britain, from Norway south and east to N. Africa, Asia, N. and S. America.

Habitats

Woodland Garden Dappled Shade; Shady Edge; Ground Cover; Bog Garden;

Edible Uses

None known

Medicinal Uses

Astringent Diuretic Tonic Vulnerary The root is astringent, diuretic, tonic and vulnerary[4, 7, 21]. It is useful in the treatment of jaundice and removing obstructions of the viscera[4]. The fronds are used to make compresses for external application to wounds and rheumatic joints - for which purposes they are fairly effective[7]. An infusion of the fronds, combined with wild ginger roots (Asarum species) has been used in the treatment of children with convulsions caused by intestinal worms[257].

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[200]. 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[172].