Once considered a single species across its range in North America and eastern Asia, Adiantum pedatum is considered to be a complex of at least four vicariant species ( Adiantum pedatum and Adiantum aleuticum occur in North America) whilst two other very closely related species can be distinguished - one in China and at least one in Japan. Adiantum pedatum in the strict sense is restricted to deciduous woodlands in eastern North America[]. See also Jin-Mei Lu et al; 'Biogeographic disjunction between eastern Asia and North America in the Adiantum pedatum complex (Pteridaceae)' American Journal of Botany Vol 98 No 10 pp 1680 - 1693.
We are treating Adiantum aleuticum as distinct here but, lacking validly published names at present(2016) for the Chinese and Japanese forms, have retained them under Adiantum pedatum[].

Common Name: Northern Maidenhair

General Information

Adiantum pedatum is a deciduous fern producing a cluster of fronds 40 - 75cm tall from a shortly-creeping rhizome that, in time can form large clumps. The fronds are lax-arching or pendent, often densely clustered[].
The plant is harvested from the wild for local use as a medicine and source of materials. A very ornamental plant, it is often grown in gardens.

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

, ,

Range

N. America - Alaska to Quebec and Nova Scotia, then south along eastern N. America to Oklahoma and Georgia. E. Asia

Habitat

Rich, deciduous woodlands, often on humus-covered talus slopes and moist lime soils, from sea level to 700 metres[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Deciduous Fern
Height	0.45 m
Growth Rate	Slow
Cultivation Status	Wild

Cultivation Details

It does not always succeed outdoors in milder and moister temperate areas[]. It probably prefers to be covered in snow overwinter - could a mulch help[]?
Easily grown in average, medium, well-drained soil in part shade to full shade[]. Requires a cool moist shady position[, ]. Requires an abundance of moisture in the air and soil[]. Prefers an alkaline soil[]. Requires an acid soil according to another report.
Members of this genus are rarely if ever troubled by browsing deer[].
Plants have a slowly-increasing rootstock[].

Edible Uses

None known

Medicinal

The whole plant is considered to be antirheumatic, astringent, demulcent, emmenagogue, expectorant, febrifuge, haemostatic, pectoral and tonic[, , ]. A tea or syrup is used in the treatment of nasal congestion, asthma, sore throats etc[]. A strong infusion of the whole plant was has been used as an emetic in the treatment of ague and fevers[].

A decoction of the root was massaged into rheumatic joints[].

The N. American Indians chewed the fronds and then applied them to wounds to stop bleeding[].

This plant was highly valued as a medicinal plant in the 19th century and merits scientific investigation[].

Agroforestry Uses:

Plants can be used for ground cover when planted about 30cm apart either way, they form a slowly spreading clump[].

Other Uses

The stipe of the plant is used as an ornament in basketry[, ].

The leaves can be used as a lining for carrying or storing fruits in baskets and on racks[].

The plant is used as a hair conditioner[]. The stems have been used as a hair wash to make the hair shiny[].

Propagation

Spores - best sown as soon as ripe 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 them 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 in spring or autumn.