Plants at the center of treatment
Most medicines in the Middle Ages came from plants. They were cheap compared with imported drugs, could be grown close to home, and fitted the theory that illness was due to an imbalance of qualities, since each plant was described as warm or cool and dry or moist. This article looks at the plants themselves and the gardens where they grew, while the preparation of remedies is a separate topic.
A caution is needed. The uses listed below are traditional medieval beliefs, not recommendations. Some plants are toxic, and many traditional uses have not been supported by modern research. Nothing here should be used as a guide to treating illness today.
Monastery gardens
Monasteries kept gardens for food, flowers and medicine. A famous plan of the monastery of St. Gall, dating from the early ninth century and probably an ideal rather than a record of a built place, shows a small garden of medicinal plants close to the infirmary, with named beds. The plants listed include sage, rue, fennel, mint and lovage, among others, and the plan gives a good idea of the typical stock of a monastic physic garden.
A ninth-century poem called the Hortulus, by the monk Walahfrid Strabo, praises the plants of a monastery garden in verse, including sage, rue and fennel, and gives a sense of how gardeners thought about them. An imperial ordinance associated with Charlemagne’s time, the Capitulare de villis, lists plants to be grown on royal estates, which shows that interest in useful plants was not limited to monks.
Monastic gardens also served as places of work, quiet and learning. Gardeners cultivated beds, raised borders and sometimes enclosed spaces, and their records of what grew where contributed to the spread of plants across Europe.
Household and cottage gardens
Ordinary households grew herbs close to the house. Gardens were usually a mixture of vegetables, herbs and some flowers, and cooks and healers drew on the same plants. Housewives often had the main responsibility for collecting, drying and storing them. Wild plants were also gathered from hedgerows, meadows and woods, and people who lived near common land could forage for free.
Seasonal timing mattered. Writers recommended picking herbs at particular times of day, in dry weather, and sometimes at set phases of the moon, and drying them out of sunlight. Whether the timing rules made a difference is doubtful, though keeping plants dry and shaded does help preserve them.
Common plants and their traditional uses
The following are well attested medieval garden plants, with some typical traditional uses.
- Sage. Highly regarded and associated with health in general. It was used in drinks, for the throat and mouth, and as a general tonic. The Latin name salvia is linked to the word for “save.”
- Rue. A bitter, strong-smelling plant used for many complaints, including eye trouble and as a protection against poison. It can irritate skin and is harmful in quantity.
- Fennel. Used for digestion and to ease wind, and eaten after meals; seeds and stems appear in kitchens and medicine chests.
- Mint. Used for stomach complaints and as a stimulant and freshener.
- Hyssop. Taken for chest and cough remedies and used in cleansing rituals.
- Parsley and lovage. Both used in cooking and for digestion and as mild diuretics.
- Comfrey. Known as a plant to help mend bones and wounds, which is reflected in a popular name, knitbone. Modern guidance cautions about internal use.
- Chamomile. Used for soothing preparations, for stomach pains and sleep.
- Wormwood. A bitter plant for digestion and against intestinal worms, also used to flavor drink.
- Betony. Considered a very versatile plant, often recommended for head complaints.
- Poppy. Used to relieve pain and induce sleep, with the risk of overdose understood by careful writers.
The medieval garden also held lilies, roses and violets, which were valued for beauty, scent and symbolism as well as medicine.
Qualities and degrees
Herbs were described by their qualities and degrees. Sage might be called warm and dry, and lettuce cool and moist, and a physician matched them to the patient’s condition. This system, discussed in the four humors, meant that a plant’s use was explained as much by theory as by observation, which helps explain why some uses look arbitrary today.
Imports and substitutes
Not all medicinal materials grew in northern gardens. Pepper, ginger, cinnamon and other aromatics came by long-distance trade, and were more costly. Cheap native herbs served as substitutes, and writers often list local alternatives. Hildegard of Bingen, for instance, wrote of the properties of many northern plants in her natural history, though how much of her work reflects her own experience is debated.
Who knew about herbs?
Knowledge was passed on in several ways: by practice, by oral tradition, and by manuscripts called herbals that described plants and their uses. Many herbals copied earlier writings and sometimes illustrated plants with stylized images that are not always accurate enough to identify the plant. Gardening skill was probably more widespread than book learning, and the combination of the two shaped the typical herb garden of monastery and home.