Common Name: Royal Fern

General Information

Osmunda regalis is a herbaceous fern growing from a short, erect, massive rhizome; the fronds are usually from 30 - 200cm tall, but can reach 300cm[, ]. Plants are evergreen in warm winter areas but deciduous elsewhere[].
The plant is harvested from the wild for use as a medicine and source of materials. It is often grown as an ornamental, there are some named forms[].

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

Americas - Argentina north through Mesoamerica, central and eastern N. America to northern Quebec; W. & S. Europe to Turkey and Caucasus; N. Africa

Habitat

Fens, bogs, wet heaths and woods, on peaty soil but in well-drained places; at elevations up to 350 metres in Britain[]. Swampy areas, fens and damp woodland[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Fern
Height	2.00 m
Cultivation Status	Ornamental, Wild

Cultivation Details

Osmunda regalis has a very wide native range from the south of South America to the north of North America, as well as being found in much of Europe and Asia. Often found at moderate elevations in the tropics, it is also very cold-hardy and is know to survive temperatures down to at least -30°c.
An easily grown plant[, ], it prefers a soil of swamp mud and loamy or fibrous peat, sand and loam[, ]. Succeeds in most moist soils, preferring acid conditions[]. Requires a constant supply of water, doing well by ponds, streams etc[]. Plants thrive in full sun so long as there is no shortage of moisture in the soil and also in shady situations beneath shrubs etc[].
Members of this genus are rarely if ever troubled by browsing deer[].
Transplants well, even when quite large[].
Some named forms have been selected for their ornamental value[].

Edible Uses

None known

Medicinal

The root is astringent, diuretic, tonic and vulnerary[, , ]. It is useful in the treatment of jaundice and removing obstructions of the viscera[].

The fronds are used to make compresses for external application to wounds and rheumatic joints - for which purposes they are fairly effective[].

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[].

Agroforestry Uses:

Plants can be grown as a ground cover when spaced about 1 metre apart each way[].

Other Uses

The hairs of the plant are mixed with wool and are used in making cloth[, ].

The roots are the source of 'Osmunda fibre', this was once widely used for potting orchids and other epiphytes[].

Propagation

Spores - they very quickly lose their viability (within 3 days) and are best sown as soon as they are ripe on the surface of a humus-rich sterilized soil in a lightly shaded place in a greenhouse. Keep the compost moist, preferably by putting a plastic bag over the pot. Plants develop very rapidly, 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. Cultivars usually come true to type[].
Division of the rootstock in the dormant season. This is a very strenuous exercise due to the mass of wiry roots[].