While dinosaurs and dodo birds have come and gone, ferns have quietly carried on, requiring nothing from this Earth but a bit of sun and a square of sod in which to sink their roots.
Let’s face it, though–ferns don’t get much respect from us humans. Recently I was out photographing a stately Dryopteris clintoniana in our woodland garden, admiring its distinctive carriage and broad, yard-high fronds and pondering the dizzying diversity of this ancient clan. I was abruptly tugged from my reverie by a visitor who asked, “Why are you taking a picture of that one there? They all look the same to me.” Feeling more defensive than indignant, I was about to attempt an explanation when the blank smile of my well-meaning inquisitor made me realize it would be a big, big mountain to climb. Yes, they are almost all some shade of green, and yes, they generally have a certain “ferni-ness”–soft texture, narrowly triangular, pinnately compound fronds coming from a clumped or creeping underground rhizome–but ferns are also beautiful, undeniably alluring, and a calming and unifying presence in the garden.
In many ways masses of ferns do for the shade garden what grasses do in sun; they harmonize and unite disparate colors and textures in a perfectly natural way. In fact, a shade garden without a good compliment of ferns is simply incomplete. It is often said that in spring, even the weeds look good. There is something so fresh and exuberant about young leaves flushed with green. By the Fourth of July, though, most shade plants have ceased growing, and a few have even begun to wither. Fortunately, many ferns will keep unfurling new fronds all summer if the soil remains moist, adding a note of freshness amid the increasingly tattered foliage of their neighbors. Having been on this planet for a very, very long time, ferns have weathered the vicissitudes of a changing climate and survived the chomping of just about every herbivore thrown at them. There are not too many things that bother ferns. Yes, even deer generally leave them alone.
FERNS FOR THE GARDEN
There are ferns native to every corner of North America, from the deserts of the Southwest to the swamps of the South to the mountains and forests of the North. There are two basic types of ferns– those that run and those that clump–and each type has its place in the garden. I encourage great flowing drifts of aggressive and fast-spreading hayscented fern (Dennstaedtia punctilobula) along our driveway, where its dense light green fronds suppress weeds and require only a fall mowing to remove dead material and head back occasional woody interlopers. Hayscented fern travels on shallow rhizomes that sprout a new frond every three inches or so. Thus the fronds are spaced apart so that the whole has a unified, woven quality. Not the fern to interplant with your treasured rarities, it nonetheless thrives in the dry, rocky, acidic soils that abound on our property, and in fall turns a lovely blend of pale yellow and rust.
Other spreaders that aren’t quite so robust include the more demure New York fern (Parathelypteris noveboracensis) and the triangular broad beech fern (Phegopteris hexagonoptera). Near the house, I have planted scattered clumps of the more restrained and formal interrupted fern (Osmunda claytoniana), whose three-foot-high crosiers rise up like living sculpture each spring from a densely knitted mass of roots and rhizome, each melon-green frond “interrupted” by a short section of leaflets pregnant with blackish green spores. The nearly vertical fronds, so punctuated by this dark zone, look truly elegant–a sight I anticipate as eagerly each spring as the flowering of my trilliums. Interrupted fern takes a few years to establish, but it keeps getting better with age. It will even thrive in dry soils and full sun north of the Mason-Dixon line, though it is more robust in moist, fertile locations.
I have also planted a few ostrich ferns (Matteuccia struthiopteris) up near the house. Each single plant is a lovely green plume of yard-high fronds circling a narrow base; each one does produce new clumps, though, a foot or two away, by means of shallow, stringlike rhizomes. I have to annually dig out these new recruits in spring, or else the patch would expand to encompass the entire bed. This is the fiddlehead fern prized for its asparagus-flavored crosiers. Our plants came from my wife’s grandmother, who cultivated a large patch in her northern Maine garden to admire and to eat.
FASCINATING WOOD FERNS
If you garden in the South, by all means try the noble southern wood fern (Dryopteris ludoviciana), an equally stately specimen that thrives in the heat and humidity of a southern summer. Give it a moist soil and shade, and it will grow to a remarkable size. I have seen some large clumps with stiff, nearly vertical fronds nearly five feet tall! The narrow fronds are reluctantly deciduous, and have a deep green color and upright carriage that is unmistakable. The wood ferns are a fascinating group for the fern lover, because they are notoriously promiscuous. When you find two species growing together, they are often interspersed with natural hybrids combining the qualities of the parents. We cannot grow southern wood fern in New England, but we can grow the very similar hybrid of it and the beautiful and much more winter hardy Goldie’s wood fern (D. goldieana) called Dixie wood fern (D. xaustralis). Though not quite as tall, it has the same elegant form as its southern parent. Others to try in the North are the male fern (D. filix-mas), the large but delicate mountain wood fern (D. campyloptera), its western counterpart, the spreading wood fern (D. expansa), and the rugged evergreen marginal wood fern (D. marginalis)
With few exceptions wood ferns and most of the native ferns in our flora are deciduous, but there are some that carry their leaves resolutely through winter’s chill. The genus Polystichum contains many of these stalwarts. Anywhere east of the Mississippi, Christmas fern (P. acrostichoides) is the one to try. It produces 14-inch-long fronds that are once-pinnate, so it has a slightly coarser texture than many. The glossy, deep green fronds begin as pewter-colored fiddleheads uncoiling from a mound of last year’s leaves, which fade just as the new crop matures. It is one of the most shade- and drought-tolerant of the eastern ferns, growing even in the dim light under hemlock, pine, or spruce. Christmas fern is strongly clumping and very dependable, and works well as an occasional punctuation mark in a bed of lower groundcovers, like creeping phlox (Phlox stolonifera) or Canada mayflower (Maianthemum canadense). Christmas fern’s supersized cousin, the majestic western sword fern (Polystichum munitum) grows in the damp maritime climate from northern California to coastal Alaska. So common as to risk ubiquity, it is nonetheless as important to the regional character of the Pacific Northwest as the Douglas fir or vine maple. Unfortunately, it doesn’t thrive outside of its native climate.
A FEW FINAL FAVORITES
No fern is as widespread in North America as the lady fern (Athyrium filix-femina), and few are easier to please. It is common in Europe as well, and, along with male fern, it was one of the main subjects of the fevered Victorian fern craze of the late nineteenth century. In its typical form, it epitomizes the delicacy and gentle texture that we associate with ferns. Finely divided, light green fronds grow all spring and summer from a slowly creeping rhizome, as long as the soil remains moist. It is particularly prone to slight mutations that give rise to some curious and occasionally striking variations. There are miniature forms, semi-crested or ruffled forms, and my favorite, the cross-hatch lady fern named ‘Victoriae’ It has alternating ranks of pinnae (leaflets) crossed up and down in a complex, three-dimensional way. (Trust me–it’s much prettier than it sounds!) At the New England Wild Flower Society, we’ve even introduced our own popular lady fern, ‘Lady in Red’, a selected sporling with beet-red leaf petioles that contrast nicely with its lime-green fronds.
Last but not least, I’ll mention the incomparable northern maidenhair fern (Adiantum pedatum) along with its equally exquisite relative, western maidenhair (A. aleuticum). Both have tiered, many-fingered, ruffled fronds. They are, by all accounts, most folks’ favorite garden fern, and with good reason. Not only are they sublimely beautiful, but rugged and easy to establish in moist soil and partial or full shade. A third species, the southern maidenhair (A. capillus-veneris) has more triangular fronds. It can be found on wet limestone across the southern tier of the United States, and can be as lovely in the garden as its close cousins–and its more distant ferny relations, too.