Those of you who follow this column with some regularity know that I have a special place in my heart, and in my garden, for broad-leaved evergreen shrubs. Now this may sound strange to those of you in the warm and welcoming South, where many plants keep growing right through the winter; but for us here in more northerly climes, the very fact that a shrub will remain green when most others revert to mere sticks is a quality much to be prized. And of all these verdant treasures with their welcoming branches of winter green, perhaps my favorite is the common boxwood. Very few other shrubs, with perhaps the exception of holly, possess its commendable combination of delightful grace with outstanding utility.
My admiration for box is certainly not unique. Common boxwood (Buxus sempervirens) has been in Western gardens so long that there is some doubt as to where the plant was originally native. Its origins likely lie somewhere in continental Europe, but the plant was so much admired by the Romans that they very quickly spread it to the four corners of their Empire. Their principal interest in boxwood was for making topiary, a common feature in Roman gardens: easily sheared, box was more than likely the principal component of most of these elaborate living sculptures. With the fall of the Roman Empire, and with it the collapse of ornamental gardening, the cultivation of box was neglected, but the hardy little shrub simply shrugged off the loss of its more formal surroundings and escaped back into the countryside. By the Middle Ages, it was to be found growing wild all over the Continent and Britain, in numerous forms: from foot-high dwarf cultivars (later given the name Buxus sempervirens ‘Suffruticosa’) to varieties which grew to over 30 feet high and were prized for their extremely hard wood. (The wood of box is so dense that it is one of the few that actually sinks in water, and was the wood of choice for making printing blocks before the invention of etched metal plates.)
It was the dwarf form of box, B. s. ‘Suffruticosa’, which really came into prominence in the early 16th century, when it was discovered (or rediscovered, there is some debate on this) that the little plant was absolutely ideal for edging, and could be formed into the elaborate knots and designs that were then so much in vogue. Huge gardens were created throughout Europe largely from and for boxwood displays. Topiary, too, returned to vogue about this time, and the larger varieties were once again pressed into service with incredible zeal. William Cobbett, author of The English Gardener, echoed the popular sentiment that “If there be a more neat and beautiful thing in the world than box, all I can say is that I never saw such a thing.” So popular was boxwood, in fact, that it became the dominant feature in many gardens, with the inevitable backlash such horticultural monopolies often inspire. Complaining that the gardens of the day were “stuffed too thick with box,” many landscape designers of the late 18th and early 19th centuries ruthlessly ripped out centuries-old parterres and other box patterns, to be replaced with more “modern” shrubs and flowers. Once again the durable boxwood just shrugged off these changes in garden fashion: it was far too valuable and useful in the garden to be banished for very long, and sure enough, by the early 20th century, boxwood had made a triumphant return to the European gardening scene, where it remains extremely popular to this day.
In contrast to overseas, here in America boxwood was never subject to such extreme vagaries of fashion, and has remained a popular and valuable addition to our gardens since its arrival. Boxwood was one of the earliest shrub émigrés to our shores, where it adapted to the mild climates of the Mid-Atlantic and the South as if it were a native. There still exist boxwood plantings in the Virginias, such as those at Mt. Vernon and other estates along the James River, that were old when the Colonies were young. Within just a few decades, boxwood had been spread to every part of the country where it could grow with ease. One of the reasons behind this remarkable journeying is the facility with which boxwood traveled, especially in the days before rapid transport. Box roots readily from cuttings: snippets placed in damp sand and kept moist will generally root in a month or so. This meant that tiny little pots of box could be shipped by barge, boat and even covered wagon across a largely roadless country. I recently read an account of a pioneer family that was headed from their home in South Carolina to what was then the wilds of western Georgia. Just before the pioneer wife left the house where she was born, she was given some snippets of box by her mother to start her own garden. Years later she wrote back to her mother, remarking how much comfort her now grown boxwood bushes had given her: it was as if a little piece of her mother, whom she had not seen since she left home that day decades before, had in fact come along with her into the wilderness.
For me, one of the most evocative aspects of the boxwood is its scent: on warm summer days, when sunlight heats the oils in the leaves, boxwoods emit an extremely distinctive odor. While those who dislike the scent have described it as “foxy,” to me, like the smell of lilacs, this wonderful fragrance has the power to bring back forgotten memories: with the first whiff of box, I am a teenager again, on my first trip to Europe, gravel crunching underfoot, the scent of box thick in the hot golden sun, walking starry-eyed through gardens whose magnificence I had never imagined. For some reason, the air boxwood exudes seems far older than the common stuff: it’s as if it possesses some ancient, non-definable quality that cloys with the mind. To quote Oliver Wendell Holmes: “it is one of the odors that carries us out of time into the abysses of the unbeginning past: if ever we lived on another ball of stone than this, it must be that there was box growing on it.” A heady scent indeed.
If there is one legitimate objection to be made of common boxwood, it is that it is not terribly hardy (only to Zone 5b) and that in my garden at least, it is very susceptible to snow damage: the wet, heavy snows we often get in late spring inevitably mean pneumonia-inducing late night forays into the dark and freezing garden with a broom to knock the snow off the shrubs before the weight can break the branches. While nothing much can be done about this kind of snow damage once it occurs, the last hundred years or so have produced a large number of box cultivars that are remarkably more hardy than their parents. Several, like ‘Northern Find’, ‘Northland’ and ‘Inglis’, have withstood temperatures in the −20° to −30°F range, making them hardy at least to Zone 4. Those in warmer climates can even enjoy golden and variegated forms. An unfortunate (or fortunate, depending on your point of view) by-product of this selection is that few of these cultivars possess anything like the scent of the common box. If you are not a fan of the fragrance, these strains, as well as the common box’s scentless cousins Buxus macrophylla, Buxus koreana, and Buxus japonica, all bear looking into. (These types may also be better choices in terms of hardiness for the very far north and the very deep South.) Whichever you choose, do find some room for the ancient boxwood: its beauty and usefulness, especially now around the holidays, make it a first choice for your garden.
Boxwood Basics
Boxwood is a remarkably undemanding and durable plant. Indifferent to pH, it seems to grow equally well in alkaline and acidic sites. Box prefers a fertile, well-drained soil, and will grow in a considerable amount of shade. Pests are generally not a problem, though the boxwood leafminer and boxwood psyllids can cause leaf damage and deformation if not controlled. Spider mites, which can bronze the leaves, can also sometimes be a problem. All can easily be controlled by organic and inorganic means. Most box varieties grow fairly slowly — one to three inches a year (the dwarf types even less), which makes preventing snow damage extremely important — gaps caused by missing branches often require many years to fill. Shrubs can be sheared in the spring and early summer to any height or desired shape. Selected branches can also be harvested at holiday time for household decorations.
First noticed in the US about 2010, boxwood blight is a serious fungal disease that causes rapid leaf spotting, defoliation, and dieback on boxwood, often ruining plants’ appearance in a single season. It spreads by splashing water, contaminated tools, and infected plant material, and thrives in warm, humid conditions. Because there is no cure once plants are badly infected, management focuses on strict sanitation (cleaning tools and removing fallen leaves), careful selection of resistant or tolerant cultivars, and avoiding overhead watering. If you garden in an area where boxwood blight is present, it is wise to buy only from reputable nurseries that follow strict disease-free production practices.