What to know about Digitalis purpurea (foxglove) before using it medicinally

Digitalis purpurea, commonly known as foxglove, is a highly valued herb in traditional medicine, prized for its potent cardioactive properties that have been shown to improve heart health by increasing the strength of cardiac contractions and slowing heart rate.

In the garden, foxglove is a striking ornamental plant, characterized by its tall spikes of delicate, tubular bells in shades of purple, pink, and white, attracting pollinators and adding a touch of elegance to borders and containers. From a botanical perspective, Digitalis purpurea is a biennial flowering plant in the mint family, with distinctive leaves and a unique habit of growth.

Historically, foxglove has been a valuable resource in herbal medicine for centuries, with mentions in the works of ancient Greek physicians such as Dioscorides and the modern-day recognition of its cardiac glycoside properties by scientists.

This article explains the medicinal, horticultural, botanical, and historical aspects of Digitalis purpurea.

What are the medicinal properties of Digitalis purpurea?

Digitalis purpurea helps with the treatment of heart failure and atrial fibrillation due to its cardiotonic properties. It increases contractility and slows heart rate, improving cardiac output. It also lowers blood pressure and is used in the treatment of angina pectoris.

The active constituents of Digitalis purpurea are cardiac glycosides, specifically digoxin and digitoxin. These compounds increase the contractility of cardiac muscle and reduce heart rate by inhibiting the sodium-potassium pump. This leads to a decrease in intracellular sodium and an increase in intracellular calcium.

The parts of the plant used for medicinal purposes are the leaves, which are harvested in late summer and dried immediately to preserve their potency. The leaves are then ground into a powder or made into a tincture for administration. The flowers and stems are not typically used for medicinal purposes.

Possible side effects of Digitalis purpurea include nausea, vomiting, and dizziness due to its toxic properties. Ingestion of large amounts or prolonged use can lead to cardiac arrhythmias and decreased cardiac function. Prolonged use can also lead to digitalis-induced toxicity.

Precautions when using Digitalis purpurea medicinally include careful monitoring of cardiac function and electrolyte levels. It should not be used in patients with kidney or liver disease, and should be administered under the guidance of a healthcare professional due to its narrow therapeutic index and potential toxicity.

What are the horticulural aspects of Digitalis purpurea?

Digitalis purpurea grow well in partial shade and well-draining soil with a pH between 6.0 and 7.0. They prefer cooler temperatures, between 60°F to 75°F (15°C to 24°C), and high humidity. Foxgloves are hardy in USDA zones 4 to 8.

Foxgloves should be planted in the fall or early spring, 12 to 18 inches apart. Plant the seeds or seedlings in a location with good air circulation to prevent disease. Water thoroughly after planting and keep the soil consistently moist during the first growing season. Foxgloves can be transplanted, but this should be done carefully to avoid damaging the roots.

Harvesting foxgloves flowers can be done at any time, but the best time is in the morning after the dew has dried. Cut the stem at an angle, just above a leaf node, using sharp scissors or pruning shears. Remove the lower leaves to prevent the stem from becoming soggy. Harvested foxgloves can be used fresh or dried.

Foxgloves are susceptible to pests like slugs, snails, and aphids, which can be controlled with bait traps, sticky traps, or insecticidal soap. Common diseases include powdery mildew, leaf spot, and botrytis, which can be prevented with good air circulation and fungicides. Regular watering and fertilization can also help prevent disease and promote healthy growth.

What are the botanical aspects of Digitalis purpurea?

Digitalis purpurea is a biennial plant in the plantain family (Plantaginaceae). It grows 1.5 to 2.5 meters tall, with a single stem that branches off towards the top, producing tubular flowers. Its leaves are ovate, pointed, and lobed.

Its scientific name is Digitalis purpurea, and it belongs to the kingdom Plantae, class Magnoliopsida, order Lamiales, family Plantaginaceae, genus Digitalis, and species D. purpurea. The name Digitalis comes from the Greek word "digitus," meaning finger, likely referring to the shape of the seed pods.

Several cultivars of Digitalis purpurea have been developed, including 'Camelot' and 'Pam's Choice', which exhibit variations in flower color and plant height. These cultivars are bred for their ornamental value and are often used in gardens and floral arrangements.

Digitalis purpurea is native to the British Isles and Europe, but it has become naturalized in many other parts of the world, including North America, Australia, and New Zealand. It thrives in temperate climates with mild winters and cool summers.

The life cycle of Digitalis purpurea begins with germination of seeds in the spring. The seedlings develop into rosettes, which remain dormant during the summer. In the fall, the rosettes produce a single stem, which flowers and produces seed in late spring. The plant dies after producing seed.

What are the historical aspects of Digitalis purpurea?

Digitalis purpurea is a plant that has been used for medicinal purposes since ancient times. In the 16th century, it was used to treat dropsy, a condition caused by the buildup of fluid in the body. It was also used to treat other conditions such as gout and fever. The leaves of the plant were used to make a medicine that was administered in the form of a tea or a tincture.

In Greek mythology, the goddess Chloris was associated with the foxglove plant. According to legend, Chloris was the mother of Carpos, the god of flowers, and she was often depicted with a wreath of flowers, including foxgloves. The plant was also associated with the Elysian Fields, a paradise for heroes in Greek mythology.

In the language of flowers, the foxglove is associated with secrecy, mystery, and intrigue. The plant's tubular shape and showy bells are said to represent the secrets and whispers of the past. In ancient times, the foxglove was also used as a symbol of loyalty and honor.

In the historical texts of the Middle Ages, the foxglove was mentioned in several herbals, including those by Gerard and Parkinson. The herbals described the plant's medicinal properties and provided instructions for its use. The foxglove was also mentioned in several medical texts, including those by the physician and botanist, Mattioli.

In the 17th and 18th centuries, the foxglove was featured in several engravings and paintings, including those by the botanist and artist, Robert John Thornton. These works of art showcased the plant's unique beauty and provided detailed illustrations of its medicinal and ornamental uses. The foxglove's popularity as a garden plant also led to the creation of several ceramic and glass figurines, which depicted the plant in various settings.