Monastic herbs, kitchen plants, and the medieval medicine bed

A monastic herb garden was not a quaint collection of scented plants. It could serve the kitchen, infirmary, storeroom, and classroom, while also providing fragrance and beauty. Monks, nuns, and other workers needed to recognize plants, tend them, harvest the right part, and keep one bundle distinct from another. The same sage or fennel might enter food, household work, and a medical text.

Those overlapping uses are easy to romanticize. Medieval gardens varied by region, date, wealth, climate, and the needs of each community. Surviving plans and manuscripts show ideals and recorded knowledge, not a complete account of what every gardener grew or what every patient received. A neat drawing says nothing about crop failure, substitutions, plants obtained elsewhere, or the unrecorded skill of those who did the work.

The Saint Gall plan separated kinds of work

The early ninth-century Plan of Saint Gall is unusually detailed: its five joined pieces of parchment carry a proposed monastic complex with 52 buildings and 333 Latin annotations.¹ The drawing includes three garden areas. One medicinal garden lies beside the infirmary and physician’s quarters; other productive spaces serve food growing and an orchard. The arrangement treats plants as working infrastructure.

The medicinal beds name costmary, mint, pennyroyal, rue, sage, and other plants that also appear in historical recipes.² Yet the plan was an idealized proposal, not a measured record of a monastery as built. It cannot prove that every house planted those species or divided its ground in the same way. Our companion article on the careful ordering of useful plants looks more closely at that distinction.

Even the nearby infirmary requires careful interpretation. A monastic rule could make care for sick members an obligation without describing a successful cure, and historical scholars warn against treating the two as equivalent.² A garden beside a sickroom shows that plant preparations belonged to the community’s medical world. It does not tell us whether a particular remedy worked.

Harvesting made plant identity practical

Purpose mattered most when a plant left the bed. Leaves, flowers, seeds, and roots reach useful stages at different times, and cut material quickly loses the context that helped identify it outdoors. Once a stem was cut, its location was no longer a clue. Sorting separate bundles, discarding damaged growth, and keeping the harvested part recognizable reduced confusion in the kitchen or storeroom. Repeated handling also taught details that a short written name could miss: scent, leaf texture, stem shape, and season.

Drying and storage added another test. A fresh gray-green leaf can darken and curl; seeds from neighboring umbel-shaped flowers can look similar at a glance. The harvest also needed a clear destination: immediate kitchen use, drying, seed saving, or another household purpose. Labels and lists helped where they were available, but reliable knowledge also depended on people showing one another what to collect and what to leave alone.

Kitchen plants carried the daily meal

Food plants did less dramatic work than a celebrated remedy, but they mattered every day. Leafy brassicas such as colewort—an early, loose-leaved form of the cultivated cabbage species—could be picked a few leaves at a time and cooked alone or in pottage with grain.³ Herbs and greens added flavor and seasonal variety to otherwise plain ingredients.

The boundary between kitchen and physic bed remained porous. The Met’s research notes that fennel, sage, rosemary, violets, and other plants carried culinary, medicinal, fragrant, or ornamental value, while some useful species were gathered beyond the garden walls.⁴ “Useful” described a relationship, not a fixed botanical category. A plant’s role changed with the part collected, the intended preparation, and the person using it.

Books preserved knowledge and uncertainty

Medieval medical manuscripts did not form one tidy handbook. A surviving twelfth-century volume at the National Library of Medicine combines more than 40 texts, including theory, diagnosis, herbal remedies, dietary advice, and other interventions. Its sources draw on Greek, Byzantine, Arabic, and southern Italian traditions.⁵ Plant knowledge traveled through translation and compilation as well as through gardens.

Transmission preserved valuable material, but copying was not experimental proof. The NLM notes that medieval and early printed herbals often blended much older sources, and that many remedies in them have not been tested by modern science.⁶ Some woodcuts were too schematic for dependable identification. Translation could also place an old plant name into a new region where local species and common names differed. A name, picture, or long history of repetition could still carry error or ambiguity.

Historical use is not a safety claim

Pennyroyal makes the point plainly. It appears among the herbs named for the Saint Gall medicinal garden, but concentrated pennyroyal oil is highly toxic when swallowed and has caused acute liver injury, multiple-organ failure, and death; the National Institute of Diabetes and Digestive and Kidney Diseases advises against oral use.⁷ Historical presence is evidence of belief and practice, not a recommendation.

Familiar common names can also refer to different species, and risk can change with plant part and preparation. A modern gardener should never use a historical recipe to diagnose or treat illness. Pregnancy, childhood, medication interactions, allergies, and uncertain identification all raise the stakes further.

A modern bed can borrow the method

A present-day monastic-inspired bed can be honest without pretending to reconstruct the Middle Ages. Start with correctly identified culinary herbs that suit the site’s light, soil, drainage, winter temperatures, and available water. Put frequently cut plants within reach, provide serviceable paths, and label each species with its botanical name as well as its common name.

Keep plants grown for historical interest clearly separate from food, and omit hazardous species where children, pets, visitors, or accidental harvesting make them a poor choice. Record sowing, flowering, harvest, and winter survival. The old lesson is not that every herb is medicine. It is that plant knowledge becomes more reliable when observation, use, caution, and care happen in the same place.

References

1. e-codices: St. Gallen, Stiftsbibliothek, Cod. Sang. 1092, Plan of Saint Gall
2. NCBI Bookshelf: Carolingian Medical Knowledge and Practice, c. 775–900, “Setting the Scene”
3. The Metropolitan Museum of Art: “Colewort and Kale”
4. The Metropolitan Museum of Art: “Inside and Outside the Garden Walls”
5. U.S. National Library of Medicine: Medieval Manuscripts
6. U.S. National Library of Medicine: “Medieval Herbals in Movable Type”
7. NIDDK LiverTox: Pennyroyal Oil