Ferns Are For Distinctive Foliage

Rich green ferns provide distinctive texture.

Ferns are an odd group. They lack the color or fragrance of flowers, or the branch structure of shrubbery, trees or vines. Very few turn color in autumn. They provide only green foliage. Yet, as simple as this seems, the generally evergreen foliage that ferns provide is some of the most distinctive foliage that can be found in the garden.

With few exceptions, ferns are richly deep green. Only a few are lighter green or almost yellowish. The leaves, which are known as ‘fronds’, can be soft and papery, or coarse and tough. The fronds of most ferns are pinnately divided into neatly arranged leaflets; and many ferns have leaflets that are intricately lobed. Some ferns have leaves with more palmate symmetry. A few ferns actually have undivided leaves.

(Pinnate symmetry involves a central midrib or midvein to each leaf, or a central rachis that supports lateral leaflets. Radial symmetry involves multiple midveins or rachi that radiate outward from the centers of individual leaves.)

The Australian tree fern is the largest of the common ferns. It develops a broad canopy of long fronds on top of a trunk that can launch it as high as a two story home. Both the fronds and trunk of the Tasmanian tree fern are shorter and stouter. Other tree ferns are rare. The trunks are not really stems, but are thick accumulations of roots dispersed through decomposed stem tissue.

The staghorn fern is an epiphyte that naturally clings (nonparasitically) to trunks and limbs of trees. The flared upper fronds collect foliar litter that falls from the trees above to sustain the roots within. In home gardens, it is popularly grown on wooden plaques or hung like hanging potted plants, but without a pot.

Some ferns can be grown as houseplants like the classic Boston fern, which cascades softly from a hanging pot. Maidenhair fern is popular for intricate foliage on wiry rachi (leaf stems). Squirrel foot fern has lacy foliage and interestingly fuzzy rhizomes that creep over the edge of a pot.

Since almost all ferns are understory plants that naturally live on or near a forest floor below a higher canopy of trees, they are generally quite tolerant of shade. In fact, most prefer at least some sort of partial shade. This is quite an advantage for spots in the garden that are too shady for other plants. Also, many ferns can disperse their roots into soil that is already occupied by more substantial plants, even if the more substantial plants happen to also be making the particular spot too shady for other plants. In other words, they play well with others.

However, many ferns are more demanding than other plants are in regard to soil quality and watering. They perform best with rich and well drained soil, and regular watering. Sickly ferns generally respond well to fertilizer; but too much fertilizer can burn foliage. Old leaves may need to be groomed out if they do not naturally get overwhelmed by new foliage.

Rabbit Foot Fern

 

Rabbit foot fern has lacy leaves.

Rabbit foot fern, Davallia fejeensis, is one of those few plants that actually seems to be happier in pots, particularly unglazed terracotta pots that stay damp where its oddly fuzzy rhizomes creep over the edges. Besides, pots have the advantage of portability, so that appealing plants can be brought into the home as houseplants, even if only for a few months at a time. Rabbit foot ferns that lose leaves because the air in the home is too dry should recover if moved to a shady and humid spot out in the garden for a while.

The fuzzy rhizomes are as appealing as the foliage, and can creep a foot or even more if they wrap around a pot. They rot if buried, so should be spread out over the surface of the potting soil when small plants get put into larger pots. The very lacy foliage can get a foot deep in damp and partly shady spots. Foliage is shorter and more dense with more sunlight.

Scotch Moss

Sctoch moss resembles Irish moss, but is lighter yellowish green rather than dark green.

Too much water can be as much of a problem as not enough. Too much direct sun exposure can likewise be as much of a problem as not enough sunlight. Scotch moss, Sagina subulata ‘Aurea’, wants regular but not excessive watering, and only a bit of shade without darkness. To propagate, pieces with roots can be torn from healthy plants and ‘plugged’ (planted) as new plants where more are desired in early spring or autumn.

The remarkably finely textured and dense foliage makes a nicely refined ground cover for confined spots, or fills in the spaces between stones in a wall or walkway. It gets only about an inch deep, with tiny and obscured stems that get no longer than four inches. Stems develop roots where they touch the ground to creep any farther. The tiny and narrow leaves do not get much longer than a quarter inch. Tiny white flowers that bloom late in spring may not get noticed. What distinguishes Scotch moss from richly deep green Irish moss is that it is instead yellow or almost chartreuse.

Leopard Plant

Leopard plant looks like it would be at home in the garden of Kermit the Frog.

The differences between false ligularia (Farfugium spp.) and real ligularia (Ligularia spp.) are so vague that the the names are commonly interchangeable. Leopard plant happens to be a real Ligularia japonica. The round and very glossy leaves are dark green with random spots of sunny yellow. Mature plants form rather dense foliar mounds about a foot wide and nearly as high. Prominent floral trusses that bloom in late summer or early autumn are a pleasant surprise, even though the small and sometimes feeble daisy flowers are typically only dingy gold, and often have brownish centers. Both ligularia and false ligularia are understory plants that naturally prefer the shelter of larger plants, so they prefer partial shade. They also like relatively rich soil and regular watering, although once established, they can recover efficiently if they happen to briefly get dry enough to wilt.

Crested Ligularia

Crested ligularia is not what it seems.

There are so many excellent ligularia to choose from. Crested ligularia is not one of them. Although it is an excellent and distinctive perennial, it is not really a ligularia. It is Farfugium japonicum ‘Cristata’ (which actually sounds more like a hybrid of a Volkswagen and a Toyota). The slightly fuzzy and coarsely ruffled rounded leaves form grayish green mounds more than a foot high and wide. Gold trusses of small daisy flowers bloom late in summer or early in autumn. Regular watering and partial shade keep foliage full. Harsh exposure can discolor foliage during the warmest summer weather. Frost is not often a problem.

Dead Nettle

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Dead nettle has lively silvery foliage.

Because its common name is so unappealing, dead nettle is more commonly known by its Latin name, Lamium. or more specifically, Lamium maculata. It is a low and subdued plant with pastel pink, lavender or white blooms, and small deep green leaves. However, modern garden varieties have silvery variegated foliage that brightens shady spots. Some are yellowish green.

The herbaceous stems spread only one or two feet at first, but then root into the soil where they land, and continue to spread some more. The mounding growth can get about half a foot deep, or a bit deeper where it can pile up on other plants or rocks. After late spring or early summer bloom, deteriorating flower stems should be shorn back to enhance density of foliar growth below.

Stems that begin to spread a bit too far into areas where they are not wanted can be left long enough to develop roots through spring, and then pulled up and planted where they are wanted. Even before they spread that much, no one would miss a few rooted stems discretely taken from established plants to make copies. Plants in sunnier spots want richer soil and more water.

Sword Fern

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Sword fern looks like Boston fern.

This is not the native Western sword fern of forested and riparian regions here on the West Coast. This sword fern, Nephrolepis cordifolia, is native to Northeastern Australia, Southeastern Asia and Hawaii. It is naturalized in many regions beyond its natural range, and is considered an invasive exotic species in some regions. Its resiliency and reliability are appreciated in local gardens.

If it resembles the popular houseplant, Boston fern, it is because this sword fern is of the same genus. It just happens to prefer to be out in a garden rather than inside a home. Much or even most of the light green foliage stands more upright, rather than cascading from pots or elevated planters. Foliage of mature plants can get almost three feet high, with an even broader horizontal reach.

In fact, sword fern is notorious for sneaking around the garden and spreading wider than just a few feet. It is not particularly aggressive about. It creeps slowly but steadily until someone eventually notices that it has gotten a bit too prolific. Their abundant runners are wiry and strangely hairy, and produce small round tubers. Foliage can be yellowish if not watered enough in sunny situations.

Western Sword Fern

90911Within its natural range on the West Coast between the southern extremity of Alaska and the southern extremity of California, Western sword fern, Polystichum munitum, is the most common of the native ferns. A few disjunctive wild colonies live as far inland as the Black Hills of South Dakota. Yet, with few exceptions, Western sword fern is difficult to cultivate outside of the natural range.

A fern that is so resilient and undemanding seems like it should be more adaptable. Although foliage is fuller and richer green with regular watering and occasional fertilizing, established plants do not need much at all. They survive in the wild here, with naturally limited rainfall, and just go dormant if they get too dry. Symbiotic soil microbes might be their limiting factor in foreign regions.

The dark evergreen and pinnately compound fronds get about two or three feet long, but can get more than four feet long in damp and partly shady situations. They form thick mounds that mostly obscure lower old fronds that die after their first or second year. Since it is naturally an understory species, Western sword fern prefers somewhat rich soil, partial shade and shelter from dry wind.

Shade Can Be An Asset

90911thumbJust about every home garden has some sort of shade. Even if there are no substantial trees or shrubbery, there are northern walls of homes and garages, and they likely have eaves that extend their shadows a bit farther. Fences to the south create shade to the north. Gardens of modern homes are smaller, and surrounded by higher homes and fences, so are shadier than older gardens.

Those who enjoy gardening tend to enjoy more trees and substantial shrubbery than those who do not enjoy gardening, so generally contend with more shade. It is both and asset and a liability. Cooling shade makes outdoor living spaces more comfortable in the heat of summer, but limits what we can grow. With very few exceptions that are not worth mentioning, all plants need sunlight.

Fortunately, many plants need less than others. Of these, many are understory species, which live in the partial shade of larger plants in their natural environments. Not only do they naturally need less sunlight, many prefer to be in partially shaded or sheltered situation. Their foliage and bloom can be scorched by sunlight if too exposed, especially while the weather is warm, windy or arid.

Plants that prefer partially shaded and sheltered situations are characteristically different from those that prefer more exposure. Their leaves tend to be bigger and darker green to absorb more sunlight. Those that are sensitive to frost may prefer shelter from evergreen shade. To compete for pollinators with bloom above, flowers may be either bigger and more colorful, or more fragrant.

There are, of course, many exceptions. Ferns are probably the most familiar foliar plants for shade, but provide no bloom. Cast iron plant is comparable to fern for providing rich green foliage, but with insignificant bloom. Caladium, coleus and hosta are grown for lush foliage that is strikingly colorful instead of rich green. Hosta contrarily blooms with pastel flowers that are not even fragrant.

Kaffir lily, calla, hydrangea, azalea, rhododendron and impatiens provide more color for partial shade.

Iochroma

90731It is gratifying to see renewed interest in this old fashioned flower. Naturally occurring varieties of some of the nearly three dozen species of Iochroma were popular decades ago. Some might actually be naturally occurring hybrids that have yet to be identified. Many modern cultivars (cultivated varieties) were intentionally bred or hybridized for more compact growth and profuse bloom.

Old fashioned varieties of Iochroma are occasionally seen as large rampant shrubbery or even small trees in old established landscapes. Modern cultivars are more compact and manageable. For the fullest and most vigorous growth in summer, they can be pruned aggressively as winter ends, but should otherwise be pruned only for shape and confinement. They should never be shorn.

If Iochroma resembles angel’s trumpet, it is because they are related. The foliage is very similar, although the leaves are smaller. The narrowly tubular flowers are much smaller and clustered. The hummingbirds who like them so much do not even need to reach their beaks all the way in. Bloom is purple, blue, red, pink or maybe white or yellow. Iochroma happens to do well in partial shade.