Along the Edges of an Herb Garden

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The edge of an herb garden—where it meets the grass, or greets the street, or curves around a path—is a special place. The boundary shapes and defines the garden space, giving a sense of serenity and order to the lushness it frames. It can draw the eye with splashy color or entice the nose with heady fragrances.

Yet edges also pose challenges to the gardener and landscaper. They are the most visible and the most accessible—the first parts of the garden that we see and smell and touch. Shape, color, texture, and scent are used nowhere more strategically than at the edges. At the same time, they are often subject to the most abuse, from trampling to pets to rampant kids. These areas of transition between garden and landscape deserve some attention.

Though the shape and nature of the outside edges are often defined by walls, fences, streets, property boundaries, and other immovable barriers, the inside edges are more subject to our whims and wiles. They offer a wide range of possibilities to the gardener.

From Form to Function

Every herb garden, even the smallest, needs a basic shape. Meticulous vegetable gardeners pride themselves on tidy straight rows and neat square corners, and their herb-gardener counterparts snip and shape precise curves and spirals in their formal knot gardens. However, herbs are versatile, lending themselves equally to curving, flowing, more asymmetrical designs. The prettiest herb gardens I’ve seen retain an air of wildness. They are surrounded by mounds of silvery gray santolina, sweeps of flowering lavender and hyssop, thymes scrambling over the edges and around the curves. The fresh randomness and wild appeal are restrained but also accentuated by the basic shape of the bed.

Designing the Edges

In laying out a garden, you must first determine the edges. I begin with a shape (usually free-form) in my mind and transfer it to a design on paper. In the garden, I lay out the straight lines with pegs and string, and drag out garden hoses to approximate curves. Some people mark the boundaries with flour; some cut templates of carpet or cardboard to define smaller shapes.

In deciding which herbs to plant to make the best use of these spaces, I consider several factors: scent, color, size and shape, and function. The guidelines below are based on my reading and experience, as well as talking with other gardeners.

Scent is a tease, a lure, a promise. It acts as a magnet not only to those who stroll through the garden, but to the bees and butterflies that provide a daily show. In his excellent book, Landscaping with Herbs (Portland, Oregon: Timber Press, 1987), James Adams says, “Fragrance is nature’s most powerful come-on, that no creature can foreswear.” Bring some of the most fragrant herbs out to the edges, to release their scent as they’re brushed by passersby.

Bee balm, lemon balm, winter ­savory, and the lavenders, catmints, santolinas, chamomiles, and thymes are all valuable for their accessible scents, so plant them toward the edges, and take a deep breath when they brush against your legs. These herbs as a group are better behaved, too, than most of the fragrant but rampant mints. In choosing among these edging herbs, consider their flower colors in relation to others nearby in the garden. Give large-leaved costmary, with its minty camphor scent, a place of its own toward an edge, as it may grow to 3 feet tall and 2 to 3 feet wide.

Color is the arena in which the gardener turns artist, stepping back to view the scene as a whole and using color to unify and balance the effect. Echoing a large splash of color in the interior with a smaller patch of the same hue at the edges can tie the design together, catching the eye and drawing it inward to the depth of the garden. Color is as potent a lure as fragrance. A border of brilliant red spiky bee balm flowers can lead the eye down the garden path as fetchingly as its subtle, musty citrus scent can entice the nose. Let the color of the adjoining hardscape complement the plants and flowers. A cool red brick path or garden edging accentuates the delicate mauves and pinks of mint, catmint, and chive blossoms as well as the green of the foliage. The gray-green or variegated foliage of garden sage or its cultivars provides a pleasing accent and visually defines edges adjacent to lawn grass.

Size and shape of the herbs are critical to achieving an effective edge. An old-school rule places the smallest plants in front, the medium-sized ones behind them, and the tallest ones to the rear. That layout may be functional, but it can be boring as well. Instead, accent a favorite large herb by bringing it to the edge; place tall, feathery fennel at the front or at a curve in the path to encourage visitors to peek beyond it and discover new vistas. Experiment. One gardener I know uses giant sunflowers on both sides of a path to create a tunnellike corridor that opens onto her cottage garden.

Combining contrasting sizes, shapes, and textures along the edges is effective in the informal contemporary garden. Billowing borders of herbaceous perennials soften edges, as do the low-growing thymes that spread and cascade down the sides. Choose plants that can clump together or spread out as a mat, as opposed to those that need their space.

A line of herbs of the same species and size marching along the front of a border can frame and tie together a variety of more dramatic flowering herbs in the background. Pick low-growing kinds that won’t obscure the herbs you’re trying to show off. Lavender makes a loose, informal, and hardy border, but its 2-foot height may be too tall for some situations. Santolina, wall germander, curry plant, dwarf box, hyssop, and winter savory are other possibilities. These can be clipped for a more formal effect.

As you choose herbs to plant at the edges in spring, envision how they will look later on when they flower and set seed. Neat clumps at the beginning of the season may flop open unattractively; vigorous plants may verge on weediness by late summer. Experience will tell you which plants deserve a less conspicuous place in the garden and which, like the nepetas, can be disciplined by cutting them back to the ground after they flower.

Function is an important consideration in planning edges, and especially so for herbs, which are by definition useful plants. If your garden interfaces with a patio, planting English pennyroyal at the front may help discourage mosquitoes and will make outside dining more pleasant visually. You can soften the harsh shape of eyesores such as the concrete sidewalk protected by city ordinance by letting woolly or crimson thyme (Thymus praecox subsp. arcticus ‘Lanuginosus’ or ‘Coccineus’) spill out along the edges. Choose yarrow or horehound—the toughest of tough herbs—to border that dry, dusty driveway that smells of motor oil. And are you partial to moonlight strolls around the garden? Planting frosty-leaved lamb’s-ears along the edges will make the path more visible at night.

Thyme, the smaller yarrow species, and Roman chamomile (Cham­aemelum nobile) are useful along edges that may occasionally be trampled. If your garden boasts a gate, plant some German chamomile (Matricaria recutita)at the entrance, where it begs to be stepped on to send out its apple fragrance. It, too, can withstand those hard, dry places where little else will grow, and it offers an invitation to bees. Pennyroyal, one of the more fragrant mints, also can handle light foot traffic.

Herbs that you can’t do without in the kitchen — basils, rosemary, chives, mints, and lemon herbs — are good candidates for the edges of a garden near your back door. In fact, edges are prime spots for herbs that are favorites for any reason.

Still, what grows on the edges shouldn’t dominate the garden or be too distracting. That’s part of the challenge of making them work.

Walkways through and around the beds are essential to reach your herbs for weeding and harvesting, but also for the simple enjoyment of the garden. The view from the patio may be charming, but being out in the middle of the garden puts you where the action is. Building walkways creates new internal edges and increases your access to favorite herbs.

Walkways can be simple and natural, or they can be elaborate and formal. Earthen paths are easy to make and inexpensive. You can cover them with a natural mulch such as bark or wood chips, which come in a range of textures. These are pleasant to walk on but can become weedy; you may want to lay down landscape fabric before putting down the chips to discourage weed growth. Brick walkways are stunning and permanent but expensive if you don’t have a ready source of bricks and the skills of a bricklayer in your pocket. Gravel paths can frame a more formal design or a southwestern look, and the stone comes in several colors. Stepping stones can be made from slate, flagstone, or cross-cut slices of tree trunks. Grass strips, wide enough for the mower, make comfortable seating when you’re working the beds They are affordable, easy to maintain, and an effective way to tie the beds visually to the lawn and the rest of the yard.

Raised beds can be the salvation of gardeners with poor soil or limited space, or those who have difficulty bending over to tend their herbs. Besides helping in weed control and improving drainage, raising the height of herb beds can add an appealing visual dimension to the garden. A few extra inches can bring low-growing herbs into a place of more prominence. Few gardeners regret the initial expense of building raised beds.

The edges of raised beds can simply mound up gently with only a crisp line formed by a steel edging tool separating the soil from a bordering lawn. Railroad ties or similar large lumber and logs have long been called to duty to edge raised beds; the tops make a handy seat for lolling or weeding. Brick also serves well, particularly for beds that are curved, and a moderately handy do-it-yourselfer can build an edge one to three bricks high without professional help. Other materials for raised beds can be scavenged: “making do” is a time-honored tradition among gardeners. Stones or even ugly cinder blocks can be used; choose herbs for the edges that spill over them to soften the contours and disguise their origins.

Where the gardens abuts a lawn, a brick or stone mowing strip can be useful. The wheels of the lawn mower travel along the strip so that the grass can be cut to the edge of the bed without threatening the herbs in it. For best results, dig a shallow trench along the edge a few inches deeper than the thickness of your brick or stone. Pack the bottom of the trench firmly, then spread a layer of sand (sandbox sand is suitable). On top of it, lay bricks or square flagstones flush with the surface of the lawn, fill the spaces with more sand, then brush away the excess.

The edges in the garden break up space and make large areas seem more intimate. They can turn a messy tangle of green into a space that looks peaceful and planned. They give the gardener ready access, which makes chores and harvesting easier. They solve problems and bring the garden closer. Consciously working with the edges, and increasing their number in your garden, can inspire a new level of creativity.

Kathleen Halloran, health and environment reporter for the daily Coloradoan in Fort Collins, Colorado, is designing the herb garden for her new home.