Shade Tolerant Species

Kaffir lily is famously resilient to shade.

Most gardens have some sort of shade. Those that are not shaded by substantial trees likely have shadows from houses or fences. Big eaves of ranch architecture make big shadows. So do tall Victorian houses. Yet, the disproportionately small gardens of bulky modern homes with high fences are shadiest.

There are not many trees that do well in shade. Most of those that do are rather small ‘understory’ trees that naturally prefer to be in the partial shade of taller trees. The many different Japanese maples are perhaps the most familiar. Vine maple is a similar maple from North America. Many dogwoods are likewise understory trees.

Eastern redbud, parrotia, strawberry tree, sweet bay and various podocarpus are not necessarily understory trees, but are quite tolerant of partial shade. However, stems that reach beyond the shade are likely to thrive at the expense of shaded parts if not pruned for confinement. For example, a fern pine (podocarpus) can be happy on the north side of a house, but can develop such a thick canopy where it gets good sun exposure on top, that lower growth gets shaded out. All palms tolerate significant shade while young, but most eventually grow beyond it.

There is more shade tolerant shrubbery to choose from, since shrubbery is naturally lower and more likely to be shaded by trees. Rhododendron, azalea, camellia, hydrangea, pieris, fuchsia, aucuba and Japanese aralia are about as familiar as Japanese maple is. Heavenly bamboo (Nandina spp.), Oregon grape, mountain laurel, flowering maple and various hollies are also worth investigating. 

Because low growing perennials are naturally lower than both trees and shrubbery, many are naturally more tolerant to shade. Bear’s breech, cast iron plant, perwinkle, tradescantia, arum and forget-me-not can be so happy in shade that they can actually be invasive. Kaffir lily, bergenia, hosta, lily turf, ginger lily, coral bells and various ferns are much better behaved.

Foxglove, cyclamen and balsam (Impatiens spp.) are good annuals for shady spots. Cyclamen is actually a perennial that deteriorates during warm summer weather, but can regenerate as weather gets cool in autumn, to bloom through winter and early spring. Balsam does just the opposite, thriving through warm weather, but deteriorating with frost. Caladium and coleus can provide remarkably colorful foliage until frost. (Foxglove is actually biennial. Caladium grows from bulbs, but is rarely perennial.)

Despite their reputation as being aggressively invasive, both Algerian and English ivies can be resilient ground covers in significant shade. Baby’s tears likewise spreads as far as it gets water. Star jasmine is more complaisant, but only tolerant of moderate shade, and will not bloom as well as it does with better exposure.

Shady Characters

Hellebore may not tolerate much arid warmth, but is impressively tolerant of partial shade.

Suburban gardens are becoming shadier. More modern homes are taller than a single story, so make larger shadows. Taller and more fortified fences likewise create more shade. Smaller garden spaces of modern homes, or of older homes that have been added onto, have less sunny area away from the shadows of the associated homes and fences. Even large gardens of low profile homes lose sunlight as shade trees grow.

Most plants that prefer or at least tolerate shade are ‘understory’ plants; which means that they naturally live in the shade of larger plants. Consequently, most of the few trees that tolerate shade do not get very tall. Vine maple, dogwood, Japanese maple, Eastern redbud and many podocarpus are small to medium sized trees. All palms tolerate some shade, although most grow tall enough to eventually get above it.  

Aucuba, boxwood, euonymus, Japanese aralia, holly, Heavenly bamboo and some pittosporums are among the evergreen shrubs that provide foliage in partial shade. Andromeda and Oregon grape have both appealing foliage and flowers. Sarcococca, daphne and gardenia flowers are not quite as showy, but are remarkably fragrant.

Rhododendron, camellia and mountain laurel provide some of the most colorful flowers in partial shade, and have good evergreen foliage while not blooming. Fuchsia and abutilon are rather lanky shrubs, but do have interesting flowers. Hydrangeas are deciduous, so can have good fall color after providing nice foliage and big billowy blooms through summer.

Both Algerian and English ivies, as well as star jasmine, are climbing vines that enjoy partial shade. (Although the ivies cling to whatever they climb, so should be confined to where they will not ruin paint or siding). Star jasmine does not bloom as well or nearly as fragrantly in shade as it does in sunny areas, but has good foliage nonetheless. Any of these vines, as well as periwinkle, is good ground cover for shady spots.

Cast iron plant and arum are not only tough perennials that produce rich deep green foliage in the shade, but can actually become invasive and are difficult to eradicate once established. Bear’s breech is comparable, with the advantage of striking flowers, but the disadvantage that it defoliates through warm summer weather. Various ferns are perhaps the most familiar and complaisant foliar perennials for shade. Lily turf is an evergreen flowering perennial, but realistically, has better foliage than flowers.

Clivia miniata, bergenia and hardier begonias are grown for their colorful flowers as much as for their rich foliage. Clivia miniata is like lily-of-the-Nile for the shade, but blooms with shorter bright reddish orange, red or yellow flowers instead of soft blue and white on tall stems. Some of the various campanulas are delicate shade tolerant perennials with pale blue or white flowers.

Cyclamen, primrose, viola, pansy, forget-me-not, foxglove and impatiens are seasonal annuals that do not mind partial shade. Cyclamen and primrose are actually perennials that can survive through summer to resume bloom the following autumn. Impatiens is actually a warm season annual for summertime that can survive as a perennial through winter.  

Poor Man’s Rhododendron

Poor man’s rhododendrons is less colorful but more perennial than the more popular busy Lizzie Impatiens walleriana.

The nursery industry is so innately unsatisfactorily lucrative, that to us nurserymen, a ‘poor man’s rhododendron’ is any rhododendron that we grow. To everyone else, it is Imaptiens sodenii, a tender perennial that gets to six feet tall and wide or even larger on plump, softly succulent stems. It succumbs to even mild frost in winter, but regenerates rapidly by summer. It prefers partial shade, and can roast if too exposed to direct sunlight on warm days. Too much shade is rarely a problem.

The two inch wide flowers are typically very pale shades of pink, lavender or slightly blushed white. At least one modern variety has brighter white flowers with reddish pink centers. Bloom continues as long as weather is warm. The seed capsules are not much to look at, but explode to disperse their seeds when disturbed. The soft, rich green leaves are about three to six inches long.

Shade Tolerant Species Genuinely Shine

Some species actually prefer partial shade.

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.

Made In The Shade

Hosta happen to tolerate a bit of partial shade.

Modern gardens are shadier now than they ever have been. Ranch houses that were popular through the middle of the last century had those classic big eaves that shaded wide margins close to the homes. Prior to that, tall Victorian houses made big shadows. Modern houses though are even bigger. To make matters worse, lots and garden spaces are smaller and surrounded by ominously tall fences; so there is less space that is not shaded by something sometime during the day.

This is why small trees, sometimes known as ‘micro-trees’, are so popular. They are all that fit into some small gardens without creating too much shade for other plants. Large shrubbery, like some of the larger types of pittosporum, and some of the smaller types of podocarpus, often function quite nicely as small scale trees. Where not too shaded, pineapple guava and New Zealand tea tree are just as effective. They only need to be allowed to develop upper canopies with adequate clearance, while their lower limbs get pruned away, instead of getting pruned to stay down low as shrubbery typically does.

Camellia, hydrangea, aucuba, Japanese aralia, Oregon grape and Heavenly bamboo (Nandina spp.) are appealing shrubby plants for shady locations. Camellias and hydrangeas of course provide impressive blooms during their respective bloom seasons. Camellias also have the advantage of excellently glossy dark green foliage all year;  but hydrangeas are bare and need pruning in winter. Oregon grape and Heavenly bamboo, which are actually related, are more subdued but look more woodsy in bloom, and sometimes provide interesting berries afterward. Aucuba and Japanese aralia do not need showy flowers because their foliage is so bold. Japanese aralia has bigger and bolder leaves, but common types of aucuba are spotted with gold.

Balsam (Impatiens spp.), which is already one of the most popular warm season annuals that is beginning to get phased in as the weather gets warmer, is not quite as colorful in the shade as it is with better exposure, but can be impressive nonetheless. Cyclamen takes shade as well, but will actually be getting phased out through late spring and summer. Cyclamen is actually a perennial that can stay in the garden (if it is not in the way of anything else) to regenerate next autumn. As weather gets warmer in spring, caladiums and coleus can provide remarkably colorful foliage for shady spots through summer and early autumn.

Various types of ferns, although devoid of flower color, provide distinctive and often bold form and foliar texture. Australian tree ferns can actually get quite large and eventually function as small trees. Baby tears is a finely textured perennial ground cover that spreads as far as it has moisture. It can actually get to be invasive.

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.

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.

Flowering Maple

60622It is impossible to say who the parents were. So many specie were hybridized to develop the many cultivars of flowering maple that the Latin name of the collective group is simply Abutilon X hybridum, which means exactly what it looks like. They are hybrids of various and rarely documented species of Abutilon. The ‘X’ dispels any doubt. ‘Chinese lantern’ is another common name.

Flowers can be yellow, orange, red, pink or pale yellowish white. They look like small hibiscus flowers that do not open all the way, and some only open half way. Many hang vertically. Some hang at about forty-five degrees. Bloom is sporadic all year, and more abundant while weather is warm. The rather sparse evergreen foliage looks somewhat like maple foliage, with variable lobes.

The largest flowering maples do not get much taller than the eaves. Short types stay shorter than two feet. Stems can be awkwardly angular, even if pruned back to promote fluffier growth. Roots can be unstable, necessitating staking or pruning to lighten the load. Flowering maple prefers partial shade, and can tolerate significant shade, but can also do well in full sun if watered regularly.