Of the native ferns, Western sword fern, Polystichum munitum, is the most common. Yet, it can be difficult to cultivate outside of its native range. Regional symbiotic soil microbes might be what limit its adaptability beyond its range. Locally in the wild, it prefers riparian situations. Within home gardens, established specimens are impressively undemanding.
As an understory species, Western sword fern should probably prefer partial shade. Yet, it can perform as well with full sun exposure. Although it appreciates organically rich soil, it can be satisfied with soil of inferior quality. New or relocated specimens need frequent irrigation as they disperse roots. Monthly irrigation can suffice for established specimens.
Western sword fern grows about two or three feet tall, but can get taller in partial shade. It might be twice as wide. The evergreen foliage is dark forest green. Individual leaves are pinnately compound and arching. New leaves mostly obscure old leaves that deteriorate after their first or second year. Shabby specimens regenerate well after getting cut back.
Ferns are an odd bunch within home gardens. They lack floral color and fragrance. They produce no fruit or vegetables. The few that are deciduous lack autumn foliar color here. With very few exceptions, they provide no shade. There is quite a bit that they do not do. Yet, they are notably popular for their lush foliage, intricate textures and distinctive forms.
Almost all ferns are a rich deep green. Some are vibrantly lighter green. A few are silvery gray or exhibit intricate silvery patterns. Most exhibit lacy textures. Several are finer than most. Several develop relatively coarse textures. Bird’s nest fern has large but undivided and glossy fronds. Holly fern exhibits coarse texture of fronds that resemble holly foliage.
Most ferns that are popular here are evergreen foliar perennials. They are therefore tidier with occasional grooming to remove deteriorating old foliage. Some extend new foliage above old foliage as the old foliage lies down. Some regenerate lushly after the removal of all their foliage prior to their growing seasons. Deciduous ferns are uncommon locally.
Ferns do not develop stems or trunks like some other vegetation does. They sprawl over the ground with fleshy rhizomes. Tree ferns grow upward only by extending roots into the deteriorating rhizomes below. Such roots are quite strong and wiry, and form what seem to be trunks. Fern roots are rather fibrous. Fern rhizomes grow in length but not diameter.
Because of their fibrous roots, ferns are complaisant to confinement within pots. Several are splendid houseplants. Boston fern is an old fashioned but familiar example. Rabbit’s foot fern, maidenhair fern and bird’s nest fern are also popular as houseplants. Staghorn ferns are weirdly epiphytic. They can grow outside on vertical boards rather than in pots.
Most popular ferns are understory species. That means that, within their natural habitats, they live in the shade of larger vegetation. It also means that, within home gardens, most tolerate partial shade. A few actually prefer it. Most ferns also prefer systematic irrigation. Although, native Western sword fern tolerates both partial shade and lapses of irrigation.
After the warm and arid summers here, ferns enjoy the beginning of the rainy season in late autumn or early winter, which is about now.
1. Adiantum capillus–veneris, Southern maidenhair fern replaces all its tired old foliage for autumn. It resembles native species of maidenhair fern, but with distinct foliar form.
2. Nephrolepis cordifolia, sword fern remains within a big pot because it can be invasive in the ground. It is directly related to Boston fern, but is not quite as soft and pendulous.
3. Dryopteris erythrosora, autumn fern is the only fern here that exhibits autumn foliar color. It is pretty, but quite diminutive. It is no bigger now than it was several years ago.
4. Polystichum munitum, Western sword fern and the next two ferns are native here. All three grow wild within some of our landscapes; and all are remarkably tolerant of shade.
5. Athyrium filix–femina, lady fern is also known locally as ostrich plume fern, but is not related. It has tender leaves with almost succulent rachises that break easily if disturbed.
6. Woodwardia fimbriata, giant chain fern has a similar foliar texture, but is bigger and more resilient than lady fern. We sometimes need to remove big superfluous specimens.
Home gardens are getting shadier as bigger modern homes occupy smaller modern lots. Bigger homes make bigger shadows. So do their bigger fences that compensate for their minimal proximity to each other. Less space within their smaller gardens extends beyond their shade. Consequently, shade tolerant species have become more popular than ever.
Also, small trees have become more popular than large trees for small modern gardens. However, more of them are evergreen to partially obscure obtrusively close homes. Their shade lasts throughout the year, and is likely darker than that of deciduous trees. It could be too dark in some situations even for shade tolerant species. Even they need sunlight.
Realistically, shade tolerant species merely require a bit less sunlight than most species. No real vegetation can survive without any sunlight. Like it or not, artificial turf can be the most practical option for the shadiest of lawns. Some potted plants can cycle around the garden, to take turns in shade and sunlight. If so, they may not need to be shade tolerant.
Most shade tolerant species perform differently with shade than with better exposure. For example, some rhododendrons that tolerate shade bloom better with more sunlight. Most species with colorful or variegated foliage are more colorful with more sunlight. Likewise, sunlight enhances autumn color for some deciduous species. Shade is merely tolerable.
Also, some shade may be dynamic. Garden space below deciduous trees can be shady for summer, but sunny for winter. Below high evergreen trees, sunlight might get through at a lower angle through winter. Major pruning or removal of vegetation can improve sun exposure if necessary. Many shade tolerant species are adaptable to such modifications.
Most shade tolerant species are understory species. They naturally live below canopies of higher vegetation. Some have big leaves and dark foliar color to maximize absorption of sunlight. Ferns are famously tolerant of shade, although tree ferns can reach above it. Kaffir lily, cast iron plant and hosta tolerate shade also. Rhododendron, azalea, camellia, andromeda and hydrangea tolerate shade as well, but need a bit of sunlight to bloom.
Rhody, Carson and I are finally on vacation in Western Washington. As usual, departure was delayed. Now that we are here, and not at work, I have not been taking pictures like I should have been. Consequently, I am deficient of pictures for Six on Saturday. Four of these six, or two thirds, are not even relevant to horticulture.
1. Sasquatch, who is also known as Bigfoot, is a celebrity of the Pacific Northwest; and is a species that is commonly considered an individual. This was in Canyonville in Oregon.
2. Portland in Oregon is the City Of Roses. This is its South Waterfront district, south of Downtown. Incidentally, most roses prefer the climates of San Jose to those of Portland.
3. Rhody enjoys rest stops. They allow him to renew his ownership of Oregon. This is the Toutle River Rest Area, on northbound Highway 5, north of Castle Rock in Washington.
4. Ferns are common within the coastal climates of the Pacific Northwest. I do not know what this fern is. The pine may be a Japanese red pine. It is in Raymond in Washington.
5. ‘Black Gamecock’ Louisiana iris is to the left within the big box to the right. It was the priority, to replace what the gophers ate last year. There is more now than then! The rest of this vegetation is a dozen or so additional perennials from Tangly Cottage Gardening! I will get individual pictures of some of them as I process them when I get back to work. The unidentified variegated foliage to the far right seems to be variegated Japanese iris.
6. Skooter approves of my exploitation of his garden. He must know that I intend to take better care of his Louisiana iris than I did last year. He was on a sunny porch at the time.
Boston fern is merely one of several cultivars of Nephrolepis exaltata. Its cultivar name is ‘Bostoniensis’. Variegated Boston fern, or tiger fern, is reputedly a cultivar of this cultivar. Its cultivar name is either ‘Variegata’ or ‘Tiger’. From a distance, it seems to be a yellower version of the original. Prettily intricate stripes become apparent with closer observation.
Variegated Boston fern is a bit smaller and a bit less vigorous than common Boston fern. Like all variegated cultivars, it works with a bit less chlorophyll. Mature potted specimens might get no wider or higher than three feet. Unvariegated Boston fern can be more than four feet from top to bottom. Both could be larger if their long fronds were less pendulous.
In home gardens, variegated Boston fern can get rather tattered through winter. It is likely to defoliate if exposed to even minor frost. This is why it is more popular as houseplants, usually in hanging pots. Such potted specimens rely on consistent watering. Diffused but bright sunlight is best. Occasional application of fertilizer enhances foliar color and vigor.
This particular situation is both too compact and too shady for these items.
Yellow and purple ‘Karma’ iris did not work out so well. To be brief, Brent and I ‘borrowed’ rhizomes of pink bearded iris after their bloom, and prior to their removal and disposal, but they bloomed yellow and purple for the following spring. Apparently, we ‘borrowed’ the wrong rhizomes, and were victims of ‘karma’ that was appropriate for the manner in which we ‘borrowed’ them.
Of course, that experience has never dissuaded me from ‘borrowing’ what I want to grow in my own garden. I am a horticulturist. I can grow just about anything that will grow here from seed, cutting or other sources of propagation material. Some is from situations from which it must be removed anyway. Some is from greenwaste piles. Some is from seed or cuttings that I find while out and about. I purchase almost nothing from nurseries.
Much of what we grow for the landscapes at work is recycled from other landscapes at work. This particular portion of a landscape is in front of a residential staff cabin. The Australian tree fern and elephant ears were installed here by a former resident who no longer resides here. Unfortunately, this situation is both too confined and too shady for them. Not only do the leaves extend over the adjacent walkway and steps, but, in response to the shade, they also grow larger and therefore more obtrusive than they otherwise would be. Because it would be impractical for them to remain within this landscape, I am not at all hesitant about recycling them into other landscapes. I am merely waiting for cooler and rainier winter weather, when they will be more conducive to relocation. The elephant ears should be dormant. I know which landscape the fern will relocate to. The elephant ears may remain canned for propagation.
It seems to be related to Boston fern because it is. Sword fern, Nephrolepis cordifolia, is a less refined species of the same genus. It does not want to live as a docile houseplant. Instead, it prefers room to grow and spread in the garden. It has potential to spread a bit vigorously though. Containment protects adjacent smaller perennials or bedding plants.
Sword fern foliage is the same light and slightly yellowish green as that of Boston fern. It generally stands more upright though. Rather than hang softly from planters, like Boston fern does, it leans outwardly. Its pinnately compound fronds can grow almost two and a half feet tall. Pinnae might be about an inch and a half long, with a slightly grainy texture.
Sword fern is not particularly discriminating about exposure, moisture or soil. It can cling to trunks of Canary Island date palms and infest their canopies epiphytically. Sword fern is greenest with regular irrigation and shelter from harsh exposure though. Its evergreen foliage can discolor and partially defoliate when distressed. Grooming might be tedious. Healthy colonies may hide their old foliage.
Ferns are foliar perennials. They provide neither floral color nor fragrance. They provide neither fruits nor vegetables. With few exceptions, they provide no shade. The very few that are deciduous are not impressively colorful for autumn here. Ferns can not grow as hedges. Nor can they become lawns. They exclusively provide distinctive fern foliage.
They do so splendidly! Most produce the sort of distinctively lacy fern foliage that ferns are famous for. Some exhibit even more finely textured and airy foliage. A few exhibit a relatively coarse foliar texture. Almost all ferns are rich and deep green. Some are lighter or slightly yellowish green. A rare few are silvery gray, or display an intricate silver lining.
Almost all ferns that are popular within home gardens are evergreen. Most benefit from occasional grooming to remove deteriorating old foliage. Some produce new growth on top as old growth lies down below. Several grow most lushly after removal of all foliage prior to their growing season. A few deciduous types of fern defoliate for their dormancy.
Ferns do not develop stems or trunks like most other vegetation does. They sprawl over the ground with rhizomes, which are fleshy stems. Rhizomes grow only in length, but not in diameter. Tree ferns grow upward as their rhizomes deteriorate below. Roots that grow through the deteriorating rhizomes form what seems to be trunks. Fern roots are fibrous.
Leaves of ferns are fronds. Such fronds of most ferns divide into pinnae, which are like smaller leaflets. Pinnae of some ferns divide into even smaller pinnae. Rachi are central stalks that suspend the pinnae within individual fronds. Ferns reproduce by spores, so lack flowers. Most ferns propagate efficiently by division of preferably dormant rhizomes.
Because of their fibrous root systems, ferns are complaisant to confinement within pots. Most ferns are naturally understory vegetation, so are innately tolerant of partial shade. Ferns that tolerate aridity as well as shade and confinement are delightful houseplants. Most ferns are very tolerant of relocation, although some must replace foliage to adapt.
Tasmanian tree fern is more tolerant of significant frost than Australian tree fern is.
The trunk of a tree fern is really just tough compressed roots growing downward through dead organic material left behind by earlier growth. The foliage and terminal shoot high on top is just like any other fern that never leaves the ground. Because such a trunk is porous, it is ideal for epiphytic plants that, in the wild, mostly cling onto trees instead of growing on the shadier forest floor. Even though most epiphytic plants are able to cling to just about anything, many prefer tree fern trunks because they can actually root into them.
The shaggy trunks of Tasmanian tree fern, Dicksonia antarctica, take decades to grow tall enough for smaller plants to be visible below the lush foliage, but are plump enough to host a rowdy party of clinging epiphytes. Most get only about four or five feet tall, with the foliage standing a few feet higher, although some old specimens in Golden Gate Park are more than fifteen feet tall, and very old specimens in their native Tasmania can get nearly fifty feet tall.
The big lacy leaves spread about six feet wide, and can reach twice as wide in shadier spots. Shade also makes the foliage darker rich green. Like almost all ferns, Tasmanian tree fern like relatively rich soil and regular watering. Unlike other tree ferns though, it tolerates frost.
Tony Tomeo 