Maidenhair Fern

Genus: Adiantum pedatum

Pronunciation: (Add-ee-ANN-tum puh-DAY-tum)

Family: Adiantaceae

• Deciduous fern to two feet tall with graceful, fanlike fronds

• Hardy in Zones 3 to 8

• Once used as medicine

• Outstanding in the wooded landscape

Native Americans and others used this handsome foliage plant to treat a wide variety of ills, but maidenhair fern intrigues gardeners primarily because of its unusual architecture, which is stunning in a woodland garden setting.

The genus Adiantum comprises more than 200 species of deciduous, semievergreen, or evergreen ferns native to tropical America, to north temperate areas in both hemispheres, and to Australia. Maidenhair fern (A. pedatum) grows in rich, moist woods in Japan, the Pacific Northwest, and much of eastern North America.

Maidenhair ferns grow in a way that is utterly different from that of any other herb you may have in your garden. Each spring, clusters of tightly coiled maidenhair fiddleheads (also called crosiers) arise from creeping underground stems (rhizomes) growing just below the soil surface. Gradually, the glossy black stems (stipes) uncoil to reveal wiry, spreading branches (rachises) that bear five to seven groups of leaf segments. These segments (pinnae) are in turn divided into alternate, heavily veined pinnules. The pinnae are held nearly parallel to the ground in an open ring.

The generic name, Adiantum, Greek for “unwetted,” refers to the fronds’ water repellency. The specific name, pedatum, is Latin for “like a (bird’s) foot” and refers to the splayed pinnae. The common name, maidenhair fern, appears to be an inexact translation of capillus-veneris, (literally, “Venus’s hair”), the epithet of a different species found in subtropical regions of both the Old and New Worlds. (Venus’s hair is a good choice for gardeners whose climate is too warm to grow A. pedatum.)

Reproduction in ferns differs markedly from that seen in flowering plants. In early summer, spore cases in clusters called sori appear on the backs of the pinnules, concealed under their rolled-over margins in this genus. In early fall, the dustlike ripe spores are released. If they land on moist soil or moss, a few of the spores may germinate and form minute, flat green prothalli, the life forms that produce the sex organs. Eventually, if conditions continue to be favorable (moist soil, an absence of fungal diseases), a sperm will fertilize an egg, which will then divide and develop into a new plant (sporophyte).

Numerous subspecies, varieties, and cultivars of maidenhair fern exist, and botanists continue to debate their classification. Most nurseries offer only the species, A. pedatum, but you may also see the cultivar ‘Imbricatum’, whose fronds grow somewhat upward rather than parallel to the ground, or ‘Miss Sharples’, whose fronds unfurl yellow-green.

Uses for Maidenhair Fern

Nineteenth-century American health practitioners made a tea or syrup of maidenhair fern fronds to treat symptoms of colds and coughs, much as their counterparts in the Old World since antiquity used A. capillus-veneris.

The tea of the latter has also been used as a beverage and the syrup used to flavor soft drinks.

Native Americans across North America found multiple uses for this herb, as the University of Michigan at Dearborn Native American Ethnobotany Database (www.umd.umich.edu/cgi-bin/herb/) shows. The Cherokee drank a tea and rubbed on a decoction of the rhizome and other materials to relieve rheumatism. In cases of fever, the tea might be taken internally as an emetic or blown over the patient’s head and chest.

Tannins and mucilage in the fern (which are common constituents of hundreds of other plants as well) may have played a role in soothing upset stomachs and irritated respiratory passages, yet these actions seem not to have been verified by modern science. James A. Duke’s Phytochemical and Ethnobotanical Databases (www.ars-grin.gov/cgi-bin/duke/) note that no biological activity has been reported for the ten chemical constituents of maidenhair fern listed under A. pedatum.

Growing Maidenhair Fern

Choose a spot that is protected from the wind and has moist, deep, well-drained soil with an abundance of humus. Maidenhair ferns thrive in full or part shade but can tolerate full sun if the soil is consistently moist. They are most effective when grown as specimen plants or in a small group and are especially beautiful when backlit.

Although they may be grown as an airy ground cover or miniature hedge, a mass planting seems to obscure the characteristic dainty frond necklaces. Maidenhair fern looks good with other native woodlanders such as Jack-in-the-pulpit and wild ginger, as well as with cultivated shade lovers, both herbaceous perennials and shrubs such as rhododendrons, laurels, and magnolias.

Gardeners disagree whether this species languishes when grown in pots (other, more tender adiantums are esteemed as greenhouse or terrarium plants). Try it yourself and make up your own mind. Maidenhair fern is perfectly hardy to USDA Hardiness Zone 3 when grown in the ground, but you may want to sink potted specimens into the ground for winter or at least mulch them well to minimize the effect of winter temperature swings.

Plants spread slowly by creeping, branching rhizomes but are not at all invasive. They are easily multiplied in late fall or early spring by cutting off small chunks of an established planting and replanting them elsewhere in amended soil.

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