A Short History of Herb Garden Design
Whatever their design or intent, herb gardens are defined not by their organization but by the plants grown in them. If an herb is a plant with a use as a seasoning, fragrance, dye, fiber, or medicine, then an herb garden is a garden of useful plants. But don't be surprised to find species that have never had any practical application alongside the useful plants in today's ornamental herb gardens—some plants are simply too appealing to be excluded on purely technical grounds. Besides, our habit of dividing plants into the "useful" and the "ornamental" is relatively new. In medieval Europe virtually all plants were assumed to have some medicinal value. In the Renaissance, medicine, botany, and horticulture began to diverge, but they were slow to part ways and did not really separate for several centuries.
Garden layouts that date back to medieval and Renaissance Europe continue to strongly influence modern herb gardeners. Though we know very little about the dooryard gardens of simpler households—the ancestors of informal cottage herb gardens, in which useful plants were grown close to hand in unstructured plantings—we do have some knowledge about the structured gardens of the great medieval monasteries and royal palaces.
The earliest visual representation of a formal garden to survive the Middle Ages, found on the St. Gall plan, dates to the ninth century. This master plan for an ideal Benedictine monastery, which was never built as planned, includes a large, rectangular kitchen garden with 18 beds of vegetables and potherbs and a smaller square garden with 16 beds of medicinal herbs. This small healing garden is located next to the doctor's house and near the infirmary. Both gardens are walled and are laid out in two parallel rows of rectangular raised beds, each bed devoted to a single species.
This basic, utilitarian design is typical not only of monastic but of other medieval gardens as well. Enclosed gardens of rural manors and townhouses are depicted in a number of 15th-century illuminations in Piero de Crescenzi's popular treatise on horticulture and agriculture, Liber Ruralia Commodorum (On the Management of Country Estates). They too are made up of a number of small square or rectangular beds arranged in a simple grid pattern. The paths between the beds allow easy access to the plots.