Create a Subversive Knot Herb Garden

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A bit of horticultural heresy, Geraldine Laufer’s asymmetrical knot garden greets visitors as they round the deck and enter the garden.

While moderngardeners rightly honor many old and venerable gardening traditions, I perceive a need for innovation and adaptation of his­torical garden designs to modern garden sites. A case in point is the Renaissance knot garden, an arrangement of low hedges tightly sheared to look like interwoven ribbons.

I have seen many traditional knot gardens in my travels, and the whole process of creating one intrigues me, so when I planned a new garden for our backyard in Atlanta, Georgia, I decided to include a knot. However, I didn’t want to just copy an old tradition; I wanted to update and personalize it and adapt it to my not-quite-square site. Thus I opted for an asymmetrical planting design, which I thought would provide a delightful surprise to visitors as they rounded the corner of the house. And the lack of symmetry, while a heresy of the Renaissance tradition, seemed better suited to our ranch-style house than a conventional knot might have been. So began what we jokingly call our “subversive” knot garden.

Nature Subdued and Directed

The knot garden has its roots in the Middle Ages, when fragrant shrubs such as lavender and rosemary were planted as hedges within castle walls and maintained with flat-clipped tops. Newly laundered clothing and linens were spread over the hedges to dry so that the herbs might impart their scent to the ­items. During the Renaissance, the patterns for these hedges became increasingly ornate, and the knot garden was born.

Accounts of payments to gardeners for “diligence in making knot” and for “clypping of knottes” appear in English records as early as 1502. Knots were popular with Elizabethans for at least 100 years and were viewed with satisfaction from the upper windows of Tudor cottages and mansions alike. It was only in the early decades of the seventeenth century that Francis Bacon scoffed at them as “toys” and the herbalist John Parkinson derisively called them “curious knotted gardens”.

Traditionally, knot gardens were square and bilaterally symmetrical, one half a mirror image of the other. They were edged with lead strips about 4 inches high, oak boards, tiles, or even the shank bones of sheep to “prettily grace out the ground”, according to Parkinson in Paradisi in Sole, Paradisus Terrestris (1629). Intricate planting plans appeared in many of the herbals and husbandry books of the period as guides for the gardener laying out a knot. The patterns might be copied or modified for a particular site.

Contrasting foliage colors were chosen to emphasize individual “ribbons”. For example, the silver of lavender and the bright green of green santolina stood out from the dark greens of boxwood and germander. Low, dense plants such as thyme, hyssop, thrift, gray santolina, rosemary, and–later–dwarf box, juniper, and yew also lent themselves to the formation of interlaced heraldic or geometric designs.

The over-and-under basket-weave effect so important to the knot garden was accomplished by the way the hedges were planted and pruned. For instance, a row of boxwood was planted in a ­pattern. Next, a row of lavender was planted right up to both sides of the boxwood, appearing to disappear underneath it. Clipping the lavender slightly lower than the height of the boxwood exaggerated the woven effect.

Plants were also chosen for their ability to withstand close clipping because knots were maintained for dozens of years at the same height. Slow-growing plants reduced the frequency of shearings needed each year.

The garden was called an “open knot” if the soil between the hedges was neatly raked or covered with different colors of gravel or earth. In The English Husbandman (1613), Gervase Markham recommended brick dust for red earth, ground lime or chalk for white, coal dust for black, powdered yellow clay or sand for yellow, and a mixture of white chalk and coal dust for blue. (Directions called for these to be sifted and beaten to a powder with a “beetell”, a large, heavy wooden mallet or pestle.) If paths pierced the knot, dividing it into four quadrants, it was also considered an open knot.

On the other hand, the garden was termed a “closed knot” if the areas between the hedges were solidly filled with flowers. The wealthy might fill their knots with rare tulips from Turkey. Less exalted personages grew pinks and ­carnations, Johnny-jump-ups and violas, primroses, lilies, English daisies, ­calendulas, and wallflowers in the spaces between the hedges.

A Knot For The Nineties

The challenge in including a knot in my garden plans was that ours is not a Tudor mansion but a 1950s brick ranch–albeit one with a deck that overlooks the whole backyard, providing a perfect spot for viewing a knot garden from above. Pressed into service, my graphic designer husband, David, came up with a wonderful offbeat plan, complete with curlicues and diagonals, for an area about 20 by 24 feet. His design took into account the mature width of the hedges (between 18 inches and 2 feet) rather than being simply lines to indicate the placement of the plants.

I improved our red clay soil with rich topsoil and lots of well-rotted manure and coarse river sand (because herbs grown as hedges generally need excellent drainage). Following a soil test, I added pulverized dolomite lime to nudge the acidic soil to a more neutral pH. After I tilled in all the amendments, the area looked like a chocolate cake. Lacking sheep shanks, I edged the rectangle with bricks set on edge. We transferred our planting plan to the ground, stretching string between two stakes for straight lines, laying out curves with flexible garden hose, and marking the outlines on the soil with lime.

My plant list concentrated on contrasting colors for the different ribbons in the knot. Taking my cue from En­glish gardening books, I began with dwarf English boxwood, gray santolina, lavender, and germander. I also included Crimson Pygmy dwarf barberry for two of the ribbon strands. ­Although barberry is deciduous, I reasoned that enjoying ten months of the terrific maroon foliage would more than compensate for two months without leaves.

So that the low herbal hedges would grow together evenly, I needed to start with young stock very closely spaced, and so I began with inexpensive liners, small rooted cuttings from a nursery. It was a good thing that they were inexpensive because I needed dozens. All plants were planted on 8-inch centers. A ribbon 16 feet long thus required twenty-four liners; a curlicue, eighteen, and so on.

Paradise Lost–And Regained

It was an exciting day when planting began, but alas, you could hardly see the lines of tiny plants against the background of the soil. I had to instruct visitors to look for the lime, stakes, and string if they wanted to see the design.

The liners grew strongly the first ­season, but the traditional English choices for herbal hedges couldn’t withstand our Atlanta climate. The first winter, we had record low temperatures, and only 8 of the original 100 boxwoods survived. The following summer was exceptionally hot and humid, with a downpour every afternoon at four, and the gray santolina and lavender gave up the ghost. Each time I had a casualty, though, I replaced the plants with ones better adapted to our growing conditions. Dark green dwarf yaupon holly succeeded the dark green boxwood. Because the crimson barberry was doing exceptionally well, golden barberry replaced the gray santolina. Pale green variegated privet followed the silver lavender.

Once again, the young plants grew strongly, knitting themselves together by the second year. I carefully manicured them with rechargeable electric hedge shears to train them into low, mounded hedges. Unfortunately, the new plants had widely varying rates of growth. The dwarf yaupon holly and the barberries needed shearing only once a year, but the variegated privet quickly threw out flexible shoots and needed a haircut every six to eight weeks to limit its height to 18 inches. As I got to know the idiosyncrasies of the different plants and as the garden gained some age, the knot began to look good. While I had begun with the traditional raked soil in the spaces between the herbal hedges, I eventually added a nontraditional wood-chip mulch to control weeds and to cut down on maintenance.

Now at the end of their eleventh season, the asymmetric ribbons of our subversive knot garden have achieved a smooth uniformity, lively in color and breathtaking in effect. It is a great conversation starter when guests come to visit. But while the finished knot is lovely, the fun was in the doing.

Geraldine Adamich Laufer is a dirt gardener with a master’s degree in horticulture from Rutgers University. She has served as coeditor for The Herbarist, the annual journal of The Herb Society of America, and has written articles for gardening magazines. Her herb garden has achieved national and local acclaim.