Answer: The old four square gardens were really very simple. Four equal sized raised beds, perhaps edged in wood planks or stones or perhaps a small plant such as hens and chicks, paths of beaten earth or gravel, and treasured plants. For the most part these would likely have been herbs, grown for their usefulness; the selection would have depended on the lady of the house and her preferences and needs and knowledge. In a modern interpretation, we tend to grow old fashioned herbs and plants which appeal to us. There are no firm rules for these, rather they were utilitarian herb gardens or vegetable plots or a mixture of both with perhaps a few pretty plants thrown in. The overall plantings were orderly and fairly symmetrical and quite charming.
You might find some useful plant lists, at least, in the book Plants of Colonial Williamsburg: How to Identify 200 of Colonial America's Flowers, Herbs, and Trees) by Joan Parry Dutton and published by The Colonial Williamsburg Foundation, ISBN 0-87935-042-3. Another fine book for a look at heirloom plants and their early garden uses is The Heirloom Garden: Selecting and Growing Over 300 Old-Fashioned Ornamentals by JoAnn Gardner, Storey Communications, ISBN 0-88266-751-3.
While I don't have an actual plan to offer you, you might find inspiration from the plans for a somewhat similar decorative herb garden in the Brooklyn Botanic Garden booklet "Herbs and Their Ornamental Uses" ISBN 0-945352-07-7 or in the plans for a loevely four sided fragrant cottage garden in "Rodale's Illustrated Encyclopedia of Perennials" by Ellen Phillips and C.Colston Burrell ISBN 0-87596-570-9.
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