Delta Maidenhair Fern

90904Some of us might remember Delta maidenhair fern, Adiantum raddianum, as a houseplant that was popular for terrariums in the 1970s and into the 1980s. Although quite happy in terrariums, it eventually gets big enough to crowd other plants in such tight spaces. It prefers to be potted on a porch, or in a regularly watered and sheltered spot in the garden. It tolerates quite a bit of shade.

Regular watering is important to keeping the foliage well hydrated, particularly among potted plants that are unable to disperse their roots into surrounding soil. The stolons bellow the foliage are not so sensitive, so can regenerate new foliage if partly desiccated old foliage needs to be cut back. They want good rich soil or potting media, and appreciate occasional application of fertilizer.

Individual fronds (leaves) have the potential to get as long as a foot, and half as wide, although they are mostly significantly smaller, and might be only half as long. Each frond is intricately divided into many small leaflets that are almost triangular, except that their out edges are curved and scalloped. Foliage is lighter green than that of most other ferns. Rachi (leafstalks) are black and thin.

Ferns Are Delightful Without Bloom

90904thumbMany of the most popular plants are expected to bloom to add color and fragrance to the garden. Many others are grown to produce fruit or vegetables. Some are appreciated for their foliar color in autumn. Big trees are grown for shade. Turf grasses are grown as lawn. Evergreen shrubbery makes hedges. It seems that all plants perform particular tasks in the gardens which they inhabit.

Ferns only need to provide rich foliage. They do so very efficiently, with remarkably stylish and distinctive textures, and deep green color. Most ferns are evergreen, so only need to be groomed of their old foliage as it gets replaced by new foliage. Most of the few deciduous ferns are bare only briefly during their respective dormant seasons. Some can grow wild without any grooming at all.

Many ferns are famously tolerant of partial shade that is too dark for many other types of plants. Many are tolerant of confinement, so are happy in pots, planters and small atriums, or under stairs. Some ferns that are tolerant of both shade and confinement are popular as houseplants. Those that get too big or their situations are generally easy to dig and relocate, or divide into more plants.

There are only two species of tree fern that are common here; the Australian tree fern, and the New Zealand tree fern. Australian tree fern is taller with leaner trunks. Tasmanian tree fern is short and stout. These and more rare tree ferns are the only ferns that leave the ground as they develop ‘trunks’ of tightly bundled fibrous roots dispersed through the decayed remains of their rhizomes.

Their rhizomes are just their thick herbaceous stems. Those of tree ferns do not branch into more than a single terminal bud, so can not be divided. Rhizomes of most other ferns split into clumps of a few or many individual budded rhizomes, which can be divided if they get too crowded. Leaves that grow from the rhizomes are known as fronds. The fronds of almost all ferns are divided into smaller leaflets known as pinnae, which are suspended by leafstalks known as rachi.

Colorful Foliage Fades Through Summer

P90713Autumn foliar color is not the concern yet. It develops later as deciduous plants defoliate for winter. Purplish, reddish, yellowish, bluish or gray foliar color that can be seen now is provided by plants that are colorful while actively growing. Almost all of this sort of foliage is most colorful when it is young and fresh, early in spring. Then, through summer, some of the best foliar color fades.

This process is perfectly natural. It does not imply that anything was done improperly, or that plants were not given what they need. In fact, most plants with colorful foliage would rather be green. They are mutants that were reproduced specifically for their distinctive color. Some try to revert back to green by producing greener shoots that grow faster because they have more chlorophyll.

Photinia is an odd one. By now, The rich green foliage shows no clue that it was rich reddish bronze when it developed early in spring. The foliage did not really fade. It merely matured. Then there are the newer cultivars of purple leaf plum, which maintain their color from spring to autumn. It is amazing that such darkly colored foliage that seems be devoid of chlorophyll can photosynthesise!

Some plants maintain their color better than others. Gray or bluish foliage is always gray or bluish; but admittedly, blue spruce and blue junipers are not quite as striking now as they were earlier. If red fountain grass and bronze aonium fade, it will be too slight to notice. Stems of bronze, gold or striped cannas that fade after bloom get pruned out in favor of more colorful unbloomed stems.

‘Forest Pansy’ redbud, ‘Summer Chocolate’ silk tree and ‘Sunburst’ honeylocust are notorious for fading. By now, the formerly richly bronzed redbud and silk tree merely seem to be stained with coffee. Golden honeylocust might have been bright yellow in spring, but now just looks sickly. Gold tipped and silver tipped deodar cedars can likewise be a bit pale. Bronze elderberries hold color well, but golden elderberry might now be chartreuse.P90713+

Giant Bird Of Paradise

60720Unlike the common bird of Paradise that is grown for striking bright orange flowers, the giant bird of Paradise, Strelitzia nicolai, is grown for strikingly lush foliage. The big rich green leaves get nearly six feet long, and flare outward from leaning trunks that can eventually reach upstairs eaves. Foliage is healthiest if sheltered from harsh sunlight (such as hot reflected glare), wind and frost.

Bold white blooms with contrastingly delicate blue streaks are a rare surprise on older trunks. The navy blue floral husks with nectar dripping from them look like the beaks of drooling seagulls; but the flared flowers above look like the crests of parrots.

Foliar Color Long Before Autumn

51104The best and brightest color in the garden is obviously still provided by flowers. Autumn color can be spectacular, but only amongst relatively few deciduous trees, shrubs and vines that turn color reliably in mild climates, and only if the weather is conducive to coloration. The next best option for color beyond green is the sort of colored foliage that does not wait for autumn to materialize.

Foliage can be shaded with varying degrees of yellow, red, pink, purple, bronze, grayish blue or gray, or variegated with white, yellow or silvery gray. Plants that display such colorful foliage can be as small as flowering annuals, or as substantial as shade trees. Many are deciduous plants that also turn color in autumn. Most of the best are actually evergreen, so hold their color through winter.

Color tends to be richest as new foliage emerges in spring, and fades more or less through summer. Gold junipers only start out gold, but then fade to green within only a few months. The purplish foliage of ‘Forest Pansy’ redbud fades to coffee stained green. Yet, bronze New Zealand flax is always bronze. Dusty miller is always gray. Some plants are more reliably colorful than others are.

Exposure is important too. Most blue or gray foliage, whether juniper, agave, spruce, eucalyptus, olive or silver Mediterranean fan palm foliage, will be significantly greener if shaded. However, white variegation of English holly, hydrangea, ivy, hosta and pittosporum have better contrast if partly shaded. Colorful Japanese maples color better with good exposure, but roast if too exposed.

Many plants with colorful foliage are notorious for developing greener mutant growth known as ‘sports’. Because sports have more chlorophyll, they grow more vigorously than more colorful growth does, and can overwhelm and replace the more desirable colorful foliage if not pruned out. Many types of white or yellow variegated euonymus, as well as the more intricately variegated New Zealand flax, can revert to monochromatic green within only a few years.

Holly Fern

60601This is one of those perennials that has mixed reviews. Although relatively tough once established, holly fern, Cyrtomium falcatum, is susceptible to rot and fungal leaf-spot. It likes to be watered somewhat regularly, but rots if the soil is constantly saturated. Leaf-spot is not as dangerous as it looks, but can be unsightly. Too much fertilizer (to correct the damage) can burn the foliage too.

Individual fronds might get as long as a foot and a half, with half a dozen to a dozen pairs glossy and irregularly toothed pinnae. Foliar texture (remotely) resemble that of some types of holly. Because they disperse their roots so efficiently, mature specimens do not like to be transplanted. Small plants can grow as houseplants for years, but eventually want to get out into the garden. Holly fern likes a bit of shade, and will tolerate rather dark shade.

Ferns Are Shady But Cool

P90309+++++It could be either an asset or a liability. With few exceptions, ferns do not want to be too exposed to direct sunlight or wind, especially during warm and dry weather. However, as long as they get just enough filtered light, they can be quite happy in sheltered spots that are a bit too shady for other plants. Most like to be watered regularly, and perhaps lightly fertilized in spring and summer.

They provide neither floral color nor fragrance. They lack interesting branch structure and bark. Since they reproduce by spores, they do not even produce any fruit, either edible or ornamental. For those who do not know them any better, they might seem to be rather boring. Yet, those of us who grow them know how handsome their lush, finely textured and uniquely patterned foliage is.

Of the popularly grown ferns, only two develop ‘trunks’, (which are actually just clustered wiry roots growing downward through rotting stems). Two others are ‘epiphytes’ that naturally cling to trees or exposed stone, but in home gardens, are more popularly grown on wooden plaques. Most other ferns are terrestrial understory perennials that naturally live in the partial shade of larger plants.

Although mostly confined to the ground, some ferns can get quite large. Individual leaves, which are known as ‘fronds’, can get several feet long. Even before it develops a trunk, Australian tree fern produces huge fronds that can shade an atrium. Other ferns with smaller leaves can spread very efficiently, and can even become invasive. Fortunately, most ferns are relatively complaisant.

The two popular epiphytic stag-horn ferns have weirdly lobed but otherwise undivided fronds. Leaves of the odd bird’s-nest fern is neither divided nor lobed. Otherwise, fern fronds are intricately divided into small leaflets known as ‘pinnae’. These pinnae are neatly arranged on opposite sides of leafstalks known as ‘rachi’. Some ferns have silvery variegation, but most are rich dark green.

Ferns innately do well in pots. Boston, maidenhair, rabbit’s foot, holly and bird’s-nest ferns are actually excellent houseplants. However, Australian tree fern and a few others shed irritating fuzz that would be a problem in the home. Most of the popular ferns are evergreen. Many consume their own deteriorating foliage by covering it with new foliage. Some ferns need occasional grooming.

Agave attenuata

60427Agaves are innately tough and undemanding. The main reason that they are not more popular in home gardens is that they are outfitted with nasty foliar spines. The worst of these spines are the distal tips of the large succulent leaves. Most agaves are also armed with shorter recurved spines on the margins of their leaves. Gardening with such well armed perennials can be dangerous.

A complete lack of foliar spines is what makes Agave attenuata such a deviant. The relatively pliable foliage forms big grayish rosettes that can get as broad and tall as four feet. Groups of these rosettes can slowly cover quite a bit of area. The plump stems below may eventually become exposed as they shed old foliage, but are they usually obscured as newer rosettes develop and grow.

The cultural preferences of Agave attenuata are also somewhat unusual. Unlike other agaves, it wants occasional watering and a slight bit of shade. If too exposed, it can get frosted in winter, or roasted in summer. Agave attenuata is also known as foxtail, lion’s tail or swan’s neck agave because its fluffy yellowish flower stalks curve downward, and maybe up again, to about six feet tall.

Mirror Plant

90227Classic but simple mirror plant, Coprosma X kirkii, was a utilitarian shrubby ground cover for many years before all the colorful modern cultivars that are so popular now were invented. Individual plants can cover quite a bit of ground without getting any deeper than two feet. It is particularly useful in coastal landscapes, because it is so resilient to wind and exposure, as well as sandy soil.

Modern cultivars are remarkably variable. Some are variegated with white, yellow or bronze, either as foliar margins or blotches. Others are very dark purplish bronze. One cultivar is dark bronze with pink foliar margins. Most of these modern cultivars have nicely rounded and undulate leaves, although some have narrow leaves that are comparable to those of the now rare original cultivar.

The more colorful modern cultivars do not grow quite as large or as efficiently as the original, so are not quite as practical as ground cover on large areas. However, they should work just as well for smaller areas, and are even better in conjunction with other plants. Some types of mirror plant are shrubbier. Yet, others cascade nicely from terraces and big planters, and over retaining walls.

Colorful Foliage Needs No Bloom

90227thumbThere is no shortage of color for the garden here in our mild climates. If we want to, we can grow various flowers to bloom at various times throughout the year. If that is not enough, we can grow plenty of colorful foliage too. Evergreen sorts can stay fresh and resilient to minor frost all winter. A few deciduous plants and warm season perennials with colorful foliage will refoliate in spring.

Besides the various shades and hues of green, foliage can be variegated with white, cream, gray, chartreuse, yellow, gold, red or pink. Such variegation can be stripes, blotches, spots, margins or lacy patterns. New spring growth of some variegated plants is blushed with pink or red. Plants with blue, gray, silvery, bronze or purplish foliage are mostly monochromatic, without variegation.

Just as most popular flowers became less efficient at their primary function of attracting pollinators, as they were bred and developed to be bigger and more colorful than they naturally were, most colorful foliage is not an an advantage to the plants that produce it. After all, foliage needs chlorophyl for photosynthesis. Variegated portions of leaves lack chlorophyl, so are much less efficient.

In fact, many variegated plants originated as mutant growths, known as ‘sports’, that appeared on unvariegated plants, and were cloned. Many try to revert back to green by producing their own unvariegated sports. These green sports grow faster with more chlorophyl, so can overwhelm variegated growth if not pruned out. Monochromatic blue or gray foliage is not mutant growth, but is instead a natural adaptation to extreme exposures, mostly at high elevations, so is not prone to reversion.

English holly, English ivy, euonymous, silverberry, New Zealand flax, mirror plant and various pittosporums are some of the more popular variegated plants. Purple leaf plum, purple smokebush and a few cultivars of Japanese maple are popular plants with purplish or bronze foliage. Blue spruce, American agave, Arizona cypress and various junipers have exquisite bluish or gray foliage.