Adiantum aleuticum Western maidenhair

Epithet means "Aleutian."

Deciduous, 11/2 to 21/2 ft. (45 to 75 cm).Zones 3 to 8.

description: The rhizome is short-creeping, producing bushels of bright green foliar fans on upright, iridescent blackish, grooved stipes. Unlike the extremely closely related (and former namesake) A. pedatum, A. aleuticum produces green, not cherry red, new growth. The stipes are one-half or more of the total frond structure and fork at their tips into two radiating and continuous branches. A close look may reveal a single fan-shaped pinnule on the rachis between the fork and the first pinnae. This is frequently present on A. aleuticum (and will be very close to the first pinnae) but is infrequent on A. pedatum (see upper left photo on page 85).

Six to eight outward-fanning pinnae per branch form pe-date foliar blades. The pinnae extend horizontally to 1 ft. (30 cm) with the entire fan measuring up to 18 in. (45 cm) across. In this species, the rounded outer blade outline does not form a continuous semicircle, as with A. pedatum, but rather is interrupted by an extended middle pinna which may be as much as 25 percent longer than adjacent pinnae. Thirty or more pairs of pinnules with semicircular, incised leading edges are shaped like the wings of eagles. Fertile pinnules have sori on six to eight oblong, fringed, outer marginal segments protected by small curtains of inrolled false indusia. Pinnules on my plants are 3/4 in. (2 cm) long by x/2 in. (13 mm) wide. Propagate (and share) by division. (See also comments at A. pedatum.)

range and habitat: Western maidenhair prefers light shade in moist, rich woodland duff. While the serpentine form is disjunct in eastern North America, the typical species is scattered about with a curious and spotted distribution in western states. Home for most populations, however, is in coastal areas from Alaska to California. The species thrives in humid ravines, will occasionally colonize shady road banks, and may settle on vertical cliffs. Look for magnificent colonies on the walls above Willaby Creek along the nature trail at Lake Quin-

Rogue pinnule on Adiantum aleuticum.

ault on Washington State's Olympic Peninsula. Farther south one of nature's most spectacular temperate fern displays is in "Fern Canyon" in northern California's Prairie Creek Redwoods State Park. Trails from a visitor's center wander towards the Pacific Ocean with a flourishing finale in a narrow half-mile (0.8-km) stretch of a gorgeous gorge. Here flowing sheets of maidenhairs cascade down 50-ft. (15-m) plus walls impressing even the least fern inclined or informed visitor. Companion plants include big trees and huge specimens of Woodwardia fimbriata luxuriating in the coastal comfort of their optimal habitat. Look too for the Roosevelt elk that graze the beach at the canyon's outflow. Bring your camera.

culture and comments: This is easily grown in western U.S. gardens and takes time to establish in eastern U.S. habitats. Give it light shade, compost, and a reliable source of water. New growth is a week or two later than the eastern counterpart, Adiantum pedatum, and by balance, the species remains green for several weeks longer into the fall. In the occasionally mild western winter, when temperatures dip only modestly and infrequently below freezing, it may surprise, tease, and confuse by maintaining a wintergreen complement of foliage.

There have been many nomenclatural "adjustments" and "realignments" since the 1980s. I find that the original segregates provide the horticulturist manageable guidelines for de-

Maidenhairs drape from the walls of California's Fern Canyon.

Adiantum aleuticum in a perennial display at Wells Medina Nursery.

Rogue pinnule on Adiantum aleuticum.

Maidenhairs drape from the walls of California's Fern Canyon.

Upright serpentine form of Adiantum aleuticum growing with Polystichum lemmonii and Aspidotis densa on serpentine soil in the Wenatchee Mountains of Washington State.

Adiantum Aleuticum Cultivars

A form of Adiantum aleuticum 'Imbricatum' in the Lyndhurst garden.

A different form of Adiantum aleuticum 'Imbricatum' in the Olsen garden.

termining differences. They include the "serpentine form" (the erstwhile Adiantum pedatum subsp. calderi), a distinctively upright, sun- and bog-loving type found in western mountain sites, especially Washington State's Wenatchee Mountains and similar habitats and occasionally in East Coast sites.

'Imbricatum' (overlapping) is a beautiful and variable low umbrella with overlapping pinnules on the typical radiating foliar fan. It comes true from spores and will tolerate brighter light than the species, but definitely not full or especially midday sun.

'Laciniatum' (jagged) is a 1- to 2-ft. (30- to 60-cm) cultivar with slender, irregular shreds of pinnules. Short-stalked, some pinnae have threadlike pinnules while others are broad and fringed-tipped. This form is rare in the United States, but grown by collectors in Britain and Germany.

'Subpumilum' (usually very small) was discovered in the 1960s by the late Seattle horticulturist-botanist Carl English, on sea cliffs on the west coast of Vancouver Island, British Columbia. He held this information carefully to protect the native site from collectors. It can even be hinted that by being studiously vague he carefully misled would be collectors. As a consequence many potential sites from northern Oregon to southeastern Alaska came under close scrutiny, all without a "sighting." He did, however, generously share spores so that this highly desirable little plant could be distributed to enthusiasts throughout the country and, in time, abroad. With various and varying designations in the nomenclature, it has been a bit of an orphan botanically. For years, I found it easier, by default, to just call it "dwarf maidenhair." And truly dwarf it is. Having spore propagated hundreds of plants, all of which consistently matured at less than 8 in. (20 cm), I agree with the late Herb Wagner in preferring to recognize it as a separate entity. While suitable for Zones 6 to 8, it is not the easiest to introduce. My most contented plants are in rich soil with good drainage and light shade. This cultivar does not tolerate heavy soil. Once established, however, 'Subpumilum' is an immensely ornamental foreground feature or functional ground cover in a mixed container planting. The pale green fronds offer a stunning contrast when planted in combination with black mondo grass, Ophiopogon planiscapus Arabicus'. Prematurely early growth should be protected from late frosts.

'Tasseled Form' has crested tips and, when available, is a handsome variant. It is not consistent from spores.

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