Loving Shade-Loving Perennials

The gardening world was in a bit of a panic in 2013 when we learned that our most beloved shade plant, Impatiens walleriana, was no longer an option for our gardens due to a disease that had wiped out virtually the entire crop from coast to coast. Whatever were gardeners going to do without their beloved impatiens?Well, these impatiens are back again, both as single- and double-flowered, but the ordeal six years ago was of little consequence to me, since I’m so biased toward perennials. So the whole panic about what to plant in the shade had pretty much passed me by.

At most, a tiny part of my garden gets a couple of hours of sun. All I know is shade and its various gradations, and the perennials that will grow in shade, from dense to dappled.

I’ve learned that just because the ground is shaded doesn’t mean that, 4 feet higher, there isn’t lots of bright light and sun—and these are the spots where my Asiatic lilies dwell. As they get a little taller, many of them need some form of staking, and yet they grow and fill the garden with their heavenly scents through July and August and look just magnificent.

There’s also the early garden that shines its cheery face in full sun during the spring, before the tall maples shade the ground below. My hardy cyclamen love to grow at the base of the maple, where it’s dry and shaded from June onward but sunny and bright from the first February flowers till the anemones finish in May, as the astilbes begin their reign of four to eight weeks, with one actually ending in October with the vibrant colored foliage of Astilbe Flash.

There are the hostas with their greens, grays and swirls of cream, with textures like velvet, ripples like pond water, and names like Rhino Hide that belie the touch of the foliage. And all this to say nothing of the flowers, which can be white to pink with some hints of blue, some tall, some short, and some so scented that hummingbirds can’t resist.

There are the scores of columbines with long spurs and short stems that seed freely and cross haphazardly to put on a new array of surprises in unexpected places each spring into early summer. The primulas, brimming with egg yolk yellows, blues, reds, and bicolors of burgundy and yellow, some only a couple of inches tall, others sending their spikes and umbels a foot above their foliage.

The heucheras—oh, they have been my weakness for years now, and I fear I’ve planted far too many! But the mix of colors on a single plant! And the mix of colors when different varieties are planted like a serpentine rivulet, twining just inside the garden’s edge as they meet and greet their cousins, the heucherellas, and close relatives the tiarellas, some of which have a trailing and spreading habit.

All this in the shade. Hundreds of varieties of plants growing in the shade, and not an annual among them. And I haven’t even touched on the ferns, the perennial begonias, the geraniums, the thalicturms, epimediums, digitalis, aconitum and, for shady wet spots, the trollius.

But I should warn you about a lamium. Lamium Anne Greenway is truly shade tolerant and has been in my garden for years, but it’s become a bit invasive and needs taming, so beware.

I could go on, but the list is amazingly long. And, of course, for those who are not risk averse, there are rarer plants, like the trilliums and the riskier hardy orchids.

But, back to the very beginning: Let’s remember that the way we perceive and define the word “shade” is not consistent from one person to another, or from one garden to another. Shade in the outdoor garden ranges from the open shade, with unobstructed overhead sky found on the north side of buildings or tall trees, to the partial or rather complete shade found under many deciduous trees—and all the gradations in-between.

Consider what causes your shady situation. Is it from a tree or a structure? Is it temporary and changing as the day and seasons change?

We have some fuchsias (yes, annuals, but not in the garden) growing in a couple of huge concrete urns. The plants are magnificent, but for a half hour each day the sun shines directly on them, and they wilt. An hour later, they’re back in the shade and fully recovered. But will that half hour of direct sun be an hour of direct sun four weeks from now?

The latter kind of shade may vary greatly depending on the character of the tree and its canopy, as well as any pruning and thinning that has been done to “open” the tree up. Species of many evergreen conifers have a heavy, unrelenting shade not very conducive to under-planting, whereas many deciduous trees provide abundant light that is filtered through the summer, while providing no shade at all in early spring, a boon to those wanting the early color of spring bulbs.

Most ornamental shade plants favor such high, filtered sunlight, provided that the trees are deeply rooted and thus not competing for water and nutrients with the species planted in their shadow. As an example, most beech and maple species exemplify canopy trees, having extensive, shallow, fibrous surface roots, which make it almost impossible to grow any shade-loving plants underneath them. Unfortunately, many landscape architects and designers don’t take this into account when planning and designing.

A homeowner’s first attempt at coping with shade is usually with a ground cover that is intended to fill the empty spot under the tree, where nothing would grow. More often than not, Pachysandra terminalis is tried and is very much overused, but it is “safe.” While it often does the trick, it is not as evergreen as touted and can die back severely in cold winters if there is no snow cover. It’s also mildly invasive. But there’s a great alternative, called Pachysandra procumbens, that’s much better behaved and more reliably evergreen.

One thing that I’ve touched on only lightly is that shade also can mean something to you and your plants besides a lack of light. In the case of large deciduous trees, the foliage canopy has an outer area, the tree’s circumference, called the drip line. This is where the tree’s coverage is at its widest point, and when it rains, this foliage umbrella enables the tree to shed a majority of the water away from the center of the tree, out to the drip line, where it falls to the ground.

This is also the spot where the most active root growth is. As a result, even during heavy rain events, the understory of the tree can remain dry to only slightly damp. It’s only during long “soakers” that this interior area—and the plants that you might want to grow in that area—get any moisture. Shallow-rooted plants may survive, while deep-rooted plants merely languish.

Most of the ornamental perennials that we rely on for shady plantings have their origin in our woods—a logical place to look—but the woods of Japan and China have also given us some surprises, especially in the saxifrage family. Saxifrage sarmentosa is a fairly common greenhouse and houseplant. It actually is quite hardy and shade tolerant. Though it is not always evergreen, it does fill in rapidly in the late spring using stolons that slide through the surface soil and set new plants about as a strawberry plant would.

A little practice, a little patience and some serious reading will allow you to not only conquer the shade but thrive in it.

Keep growing!