It’s a drizzly Sunday in June, one that requires a couple of sweaters to keep me warm. But I can’t complain when I see so many native plants thriving, obviously in their element during this cool, damp spring—ferns, wild ginger, fairy bells, goat’s beard, vanilla leaf, and many others. Western maidenhair fern (Adiantum aleuticum), in particular, which can be found in nature basking in the mist of waterfalls, appears stunningly luxuriant right now. I watch the lush fronds of a plant in my front yard, now 20 years old and nearly three feet tall and four feet wide, move silently with the slightest breeze. “Tender and delicate, but perfect in all their details, far more than any lace work—the most elaborate leaf we have,” was the way Thoreau described ferns.
If you’re wondering about Adiantum aleuticum’s genus name, it comes from the Greek adiantos, meaning unwetted, in reference to its water repellent foliage. The species name refers to the Aleut indigenous peoples of the Aleutian Islands. Although this fern was previously known as a subspecies of Adiantum pedatum, subtle morphologic differences led to its reclassification as a separate species in the early 1990s. Also known as “five-finger fern”, the common name “maidenhair” may refer to either its glossy, dark, smooth stalks or the finely textured dark root hairs that grow from a short, stout rhizome.
How it grows
A highly textured perennial with an airy, delicate-looking structure and fine-textured deciduous foliage, Western maidenhair fern grows mainly at low to middle elevations in the shady understory of moist forests and ravines, along stream banks, in rock fissures near flowing water, and even on talus slopes. It can be found in southern Alaska and the Aleutian Islands, British Columbia, Washington, and Oregon, as well as parts of California, the Rocky Mountains, and a few disjunct populations in northeastern states and Canada.
Each dark brown or purplish-black stalk (aka petiole or stipe) grows up to 30 inches in length and forks at the top into two, from which several others emerge in a fanlike pattern. Feathery pinnae (leaflets) are made up of 15-35 fan-shaped or oblong segments (pinnules), each 10-25 mm long with jagged apical margins. Like other ferns, it reproduces via spores as light as fairy dust. Spores are produced by crescent-shaped sori on the underside of pinnules, covered by in-rolled leaf margins. They can be produced during most of the growing season, but mostly in summer. For detailed info on how ferns reproduce sexually, wander over here.
Lively green foliage provides microhabitat, shelter and resting places for arthropods, amphibians, birds and other small creatures who frequent the forest floor and may in turn supply food for others. Maidenhair fern may even provide perching spots for little birds who have just left the safety of their nest and are figuring out what to do next (pictured, right)! As winter approaches, the plant deteriorates, covers the soil and eventually adds nutrients following decomposition.
Try it at home
Native ferns deserve space in our landscapes. Besides being important elements of habitat for native wildlife, they might be the best choice for shady, damp spaces that are difficult to fill. Maidenhair fern is easily grown in shaded, moist areas with soil that’s somewhat acidic, high in organic matter and drains well, so consider it in beds, borders and woodland gardens with dappled shade to full shade. In hot areas, be sure to provide enough moisture, especially before and during excessively hot periods; hot afternoon sun will scorch leaves. Space plants two to three feet apart, or intermingle them with other plants that have similar needs, allowing for a mature width of about three feet. Don’t plant crowns too deep. Reportedly, maidenhair fern is deer resistant.
Grab a partner
In the Pacific Northwest, west of the Cascades, this lovely fern will do well in the company of others in the Western hemlock/Douglas-fir plant community, including western redcedar, vine maple, trillium, sword fern, deer fern, false solomon’s seal, stream violet, western meadowrue, goat’s beard, oxalis, piggy-back plant, foam flower, wild ginger, and many others.