Signature Plants

Signature plants are plants whose outward features, according to the old doctrine of signatures, were thought to reveal their healing properties or symbolic meaning. Shape, colour, scent, taste, growth habit or position (full sun / partial shade) were read as signs by which nature pointed to a plant's power.

The underlying idea was: like heals like. Lungwort (Pulmonaria officinalis), for instance, with its lung-shaped leaves, was regarded as a healing plant for the respiratory tract, while red-flowered plants such as purple loosestrife (Lythrum salicaria) were linked to blood and circulation. The walnut (Juglans regia) too, on account of its brain-like shape, was traditionally associated with ailments of the head.

The doctrine of signatures shaped herbal medicine for many centuries. Its roots go back to antiquity and it was further developed in the Middle Ages and the Renaissance. It became particularly well known through Paracelsus, who popularised the idea that nature itself gave hints as to how medicinal plants should be used.

Typical examples of signature plants are lungwort (Pulmonaria officinalis), liverleaf (Hepatica nobilis), purple loosestrife (Lythrum salicaria), walnut (Juglans regia), mugwort (Artemisia vulgaris) and St John's wort (Hypericum perforatum). Some plants were additionally assigned to particular planets, elements or symbolic forces.

Today the doctrine of signatures is not regarded as a scientifically sound method. Nevertheless, it remains fascinating for ethnobotanical gardens and medicinal plant collections, as it links plant observation, folk medicine and cultural history in a distinctive way. In the garden, signature plants can be grouped in themed beds, inviting visitors to discover medicinal plants not only botanically but also from a cultural-historical perspective.