They don’t have showy flowers. They live in the darker recesses of our landscapes. Yet ferns are as beloved garden subjects as any other plant group. These ancient plants have been around for millions upon millions of years. Their relatives dominated the earth even before the dinosaurs came on the scene. Most modern ferns are relatively easy to grow, and there are a wide variety to choose from.
Fern leaves are called fronds and come in an astonishing array of forms. Many are divided into leaflets or pinnae to give them a feathery look. Still others, however, have undivided leaves or may be forked only at the ends. From low-growing ground covers to tall tree shapes, there is a fern for every situation. Most require consistent moisture, but there are some exceptions that are useful even in drought-tolerant gardens. Many ferns may be deciduous or partially so, but there are plenty that stay green year-round. Here are the top dozen or so genera to consider.
Maidenhair ferns (Adiantum species) are delicate-looking with thin, dark stems and bright green, fan-shaped leaflets. The most common maidenhair fern in cultivation is A. raddianum. It is often included in terrariums and mixed containers as a house plant, but it will do well in any moist, shady garden as well. Overall, it has a very soft, lacy aspect. The western native, five finger fern (A. aleuticum) have branching fronds from which it gets its common name and is also easy to grow.
In many genera of ferns, the different species have much the same leaf architecture. Not so with Asplenium. The two species that are most readily sold couldn’t be more distinct on a superficial level. Mother fern, A. bulbiferum, is very finely divided, but bird’s nest fern, A. nidum, has large leaves that are not divided at all but rise several feet into the air and may be a foot or more wide with a prominent black mid-rib. Mother fern gets its name from the multitude of tiny plantlets that form along the main stem of its leaves. They can be rooted to start new plants.
One fern that should be more widely planted is Blechnum occidentale. This species grows by underground rhizomes to slowly fill an area. The new fronds are a delightful pink that later fades to medium green. To rejuvenate the planting, cut all fronds to the ground in winter and the new growth will come out uniformly in spring. Another Blechnum species has a short, nearly woody stem like a miniature tree fern. In spite of being native to Fiji, B. gibbum is successful even in our cool coastal climate.
Japanese holly fern, Cyrtomium falcatum, is another tough customer. Its glossy, dark green leaves make it a great accent plant. The selection ‘Rochfordianum’ has more crinkles at the edges of its leaflets, giving it a most holly-like appearance. This fern is known to grow readily from spores and volunteers may spring up anywhere that the soil is continually moist
Some ferns have other interesting features. The squirrel’s foot fern, Davallia trichomanoides, has fuzzy, brown rhizomes (looking like some forest creature) that creep along the surface of the soil. Its short, finely divided fronds and ornamental rhizomes make it ideal for a hanging basket where they can be enjoyed at eye level.
Ostrich fern, Matteuccia struthiopteris, is one of the most cold-hardy ferns. Its handsome, divided fronds to five feet or so in our climate remain a healthy green through the winter. Its fiddleheads (emerging fronds) are even edible, although moderation is advised.
Although it is very common, the sword fern, Nephrolepis exaltata, is still a useful garden plant. In fact, this species is among the more drought-tolerant of the ferns. It grows by creeping underground stems and can even be a nuisance if left unchecked. Its more graceful selection, ‘Bostoniensis’ is the Boston fern beloved as a houseplant starting in Victorian times.
The hare’s foot fern, Polypodium aureum (also known as Phlebodium aureum), has large, simply divided fronds. They are an interesting blue green and somewhat glaucous, not shiny like many ferns. Fronds arise from the underground rhizomes at a distance giving this fern a very open and graceful look. There is also a selection known as lettuce fern or sold under the name ‘Mandaianum’ that has frilly-edged fronds.
There are several handsome species in the genus Polystichum. The Christmas fern, P. acrostichoides has dark green foliage whose little pinnae resemble Christmas stockings all lined up along the stem. Western sword fern, P. munitum, forms clumps of leathery fronds and, once established, can withstand brief dry periods. The new fronds of the Japanese tassel fern, P. polyblepharum, are covered with golden hairs and as they gracefully unfurl in spring, this handsome clumping fern makes a lovely show.
If you’ve received a florist’s bouquet, you’ve probably met this one. Leather fern, Rumohra adiantiformis, is dark green, finely divided, and very sturdy. Cut fronds last many days in a vase and the plants are equally tough in the garden. It eventually forms a large colony and can take some drought.
Chain ferns in the genus Woodwardia get their name from their habit of rooting again where the arching fronds touch down. New plantlets form and may be removed and potted up or left in place to increase the planting.
There are two common tree ferns. The Australian tree fern, Sphaeropteris cooperi, can attain heights up to 20 feet tall with a crown that can spread 10 feet or more. Once it has risen above the surrounding foliage, it is surprisingly tolerant of full or partial sun. The Tasmanian tree fern, Dicksonia tasmanica, doesn’t usually get quite that tall, but can form stout trunks to 10 feet or more after many years. Its fronds arise in whorls all at once instead of one or two at time as many others.
No need to collect all of them (unless you want to), but there is probably room for a fern or two in any garden.