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Comfrey (lat. Symphytum officinale) is a genus flowering plant that belongs to the Boraginaceae family (lat. Boraginaceae). It is a perennial herbaceous plant that has an upright, branched, fleshy and hairy stem that can grow up to 80 cm (2.6 ft) in height.
The black root is also branched and grows quite deep under ground. When the white root is cut, it easily breaks and cracks. The dark green leaves are simple, approx. 15 to 20 cm (6 to 7.9 in) long, quite rough and covered with tiny hairs. While the upper leaves are sessile, the lower leaves are settled on the petiole.
Purple, yellow or white flowers are bell-shaped, turned downwards, and grow from the axils of the upper leaves. They bloom during the summer and early fall.
Comfrey produces small and dark nuts, and one plant usually provides approx. 800 - 2,000 nuts per season. Comfrey grows throughout Central Europe and can be found around humid areas, by the rivers, streams and ditches or the edges of forests.
The name comfrey comes from a Latin word for herbs (herba), middle English word cumfiria, word cōnfirma in Pseudo-Apuleius, which is why the plant is often called cōnferva, cōnserva, cōnsolida. Also, the name originates from the word conferveo which means "to boil together" as it was mostly used in tea preparation to aid in healing bones.
Other popular names for the plant: Slippery Root, Oreille d' ne, Langue-de-Vache, Knitbone, Knitback, Herbe à la Coupure, Gum Plant, Grande Consoude, Consuelda, Consoude Officinale, Consolidae Radix, Common Comfrey, Bruisewort, Blackwort, Black Root, Ass Ear
There are many comfrey varieties with different characteristics, but it is generally possible to distinguish two types of comfrey according to the color of the flowers during flowering and according to the height of the shoot. This is how purple and yellow or white comfrey differs.
Other species: Prickly Comfrey, Pough Comfrey, Bulbous Comfrey, Caucasian Comfrey, Creeping Comfrey, White Comfrey, Crimean Comfrey, Tube Bumpy Comfrey, Russian Comfrey.
Purple comfrey is also called ordinary comfrey. It has a very developed thick root. When the root is cut, it is possible to distinguish the dark brown outer part and the light yellow or white inner part. The shoot of the purple comfrey can grow up to 80 cm (2.6 ft) in height. The herbaceous stem is hollow and hairy, and the leaves are alternately arranged to better absorb light. The leaflets are pointed and rough, and the branched veins on the leaves can be easily visible. When it blooms, it gives purple bisexual flowers that grow in the axils of the upper leaves. It blooms during almost the entire growing season, until early fall.
Yellow comfrey is also called the white comfrey. Like the purple comfrey, it has a very developed thick and bumpy root. The above-ground stem is annual and unbranched and can grow up to 50 cm (1.65 ft) in height, so it is slightly lower (smaller) than the purple comfrey. The stem is also hollow and hairy, and the leaves are alternately arranged. The leaflets are lanceolate and hairy. Flowering begins in April and lasts until August.
Bocking 14 is a sterile variety and therefore does not produce seeds, which is also its advantage because it does not spread uncontrollably like other varieties. It was discovered during the 1950s and can be propagated by root cuttings. In mature and strongly growing plants, it is possible to till the soil with a spatula through the piles of leaves, about 7 to 8 cm (approx. 3 in) below the soil surface. This way you’ll remove its crown which can then be divided into pieces. The original plant will recover, and any remaining piece can be propagated resulting in faster growth of the plant. When choosing a plant for propagation, keep in mind that the plant is strong and healthy and does not show signs of rust or mold.
For comfrey planting, it is necessary to know the time and methods of planting, the requirements in relation to the soil type and the most favorable temperature.
Comfrey is planted in spring or fall.
Planting from seed
Comfrey grows in various valleys or cornfields and other cultivated soils, but can also be grown in "controlled conditions" in gardens. Use a damp cloth or paper as a substrate, i.e. a hatchery. Place a cloth or paper in a pot and moisten it. Place the seeds on a moist surface. Humidity should be checked and controlled on a daily basis and don’t forget to water it if necessary. This method of planting is recommended if you plan on planting the plant before the start of the season itself, for example in late February.
Germination time is relatively long and lasts about a month or longer. When sowing in pots for transplanting, it is necessary to make a hole of approx. 1 cm and put 2 or 3 seeds, cover with soil and water with a little water.
When the plants grow to about 15 cm (6 in), they can be transplanted into the garden.
Also, if you decide to plant comfrey in early fall (October) or even later (December), it is necessary to prepare a garden bed and sow a maximum of 2 or 3 seeds per nest. It is possible to sow in shallow rows in garden beds to a depth of approx. 0.5 to 1 cm (0.2 to 0.4 in) and the distance between seeds from 20 to 50 cm (8 to 19 in).
Planting by seedling
Although comfrey can be grown from seed, the easiest and most common way to plant is to use root cuttings. In this case, the root is removed and simply planted in the desired place in the garden, where it should be buried to a depth of approximately 2 cm. For planting, you should choose a place that is wetter and not too close to the beds because the comfrey spreads very quickly and is invasive.
Comfrey grows very well on neutral soils, but it is also suitable for growing on acidic soils, both in the sun and in the shade. The most optimal soil pH value for comfrey ranges from 6.0 to 7.0. Before planting, it is good to prepare the soil by thorough watering to keep it moist and, if necessary, by adding manure.
Comfrey is suited for cultivating in a coastal or continental climate as well as moist and semi-shady edges of forests or meadows.
Comfrey is not a very demanding plant to cultivate because it contains exceptional ingredients that allow it to grow and develop successfully. However, it is necessary to know certain requirements in relation to watering, fertilizing and propagation.
Thanks to its strong and branched root, comfrey tolerates drought conditions quite well. However, regular watering will help it grow better, be stronger and form an even bigger root. It is important to water it immediately after planting.
In relation to the cultivation of comfrey, the need for water and watering is most emphasized, while fertilization of this plant is not necessary because the plant itself serves as a slurry for other plants. However, as comfrey produces large amounts of leaves during the growing season, it can be fertilized with nitrogen.
In addition, adding animal manure can have positive results if applied as a cover of the plant. It can also be covered with other nitrogen-containing fertilization options, such as cut grass.
Comfrey is great for preparing slurry because it contains nutrients (potassium, nitrogen, phosphorus) that many plants need during the flowering and fruiting phase. For example, comfrey leaves contain 2 to 3 times more potassium than manure. It is enough to gather 1 kg of comfrey leaves and leave them for about 2 weeks in 10 l of water to ferment. Stir it and cover it with an airy material on a daily basis. After boiling, the liquid should be filtered and diluted with water. For watering plants, the optimal ratio is 1:10, and for spraying, i.e. foliar fertilization 1:50. Slurry prepared this way can be used once or twice a month in the flowering and fruiting phase.
Comfrey is most often propagated by root. In doing so, it is enough to stick a piece of root in the desired moist place in the ground. It should be borne in mind that comfrey spreads quickly, so it should be planted away from other plants.
Comfrey can also be propagated by seeds. After flowering, the flower produces a fruit with many seeds, approx. from 800 to 2000 seeds during the growing season. These seeds contain elaiosomes, which are extensions on seeds that are rich in protein and fat. Also, keep in mind that elaiosomes attract ants.
Comfrey is usually not harvested in the first season because the plant needs to be established first. Later, the root, flowers and flower stalks can be harvested. The flowering plant is harvested from May to August, and the root can be taken out in the spring just before flowering, i.e. in March and April or October and November, depending on when you planted the plant. It is important to remove it before a new outbreak.
The harvested root can be dried. They should be well cleaned, cut lengthwise into cubes and then dried in the sun or artificial heat at approximately 40°C while maintaining airiness. Such dried root has medicinal properties.
Keep in mind that it should not be dried too slowly as the root can become moldy, and then decomposes its most valuable ingredient allantoin.
Diseases and pests
The use of insecticides is not necessary for the cultivation of comfrey because pests that can harm the plant are not yet known.
Since comfrey is a plant intended only for external use for the purpose of various medical conditions, the following is an overview of its medicinal properties and the health conditions for which it is used.
The parts of comfrey that are extremely healthy are the leaves and the root, while the root stands out more because it contains a higher concentration of useful ingredients.
Some of the active plant compounds found in comfrey root are allantoin, phenolic acids, mucus, glycopeptides, aglycones, saponins, and pyrrolizidine alkaloids. Of all these, the most prominent is allantoin, which stimulates the growth of bone cells, subcutaneous and connective tissue. Precisely because of allantoin, comfrey is used as one of the best medicinal plants for healing wounds, swellings, scratches, cuts, fractures and bleeding. In addition, it is an indispensable remedy for sprains, strains, tendon and muscle strains.
Comfrey is used only for external use and is a highly prized ingredient in various creams, ointments, gels, tinctures and compresses. For example, comfrey compresses can help with psoriasis, ulcers, or varicose veins.
It is not recommended to take comfrey orally because it causes various side effects, such as diarrhea, bloating, changes in circulation.
It also contains pyrrolizidine alkaloids which can be carcinogenic and adversely affect the liver. Pregnant women, children and chronically ill people should not take comfrey, and it is generally recommended not to use it for more than 4 - 6 weeks.
In 2001, the U.S. Food and Drug Administration issued a warning against the oral use of all products containing comfrey.
History and facts
Comfrey is believed to originate from Asia and Europe, and today is most widespread throughout Central Europe. Because of its healing properties, the prevailing belief was that comfrey originated from the Garden of Eden.
Also, due to its exceptional regenerative properties, the prevailing belief is that two fingers can grow into one if they were connected by comfrey and thus held for a while. This only proves how much tissue regeneration power this plant possesses.
In folk medicine, it was mostly used to treat wounds, especially purulent ones, and to treat bone pain.
In some parts, it is also called the "root for a broken leg" because it was once used in the form of compresses for faster bone healing.
Photo: Jeno Szabo / Pixabay
- Staiger C. Comfrey: a clinical overview. Phytother Res. 2012;26(10):1441-1448. doi:10.1002/ptr.4612
- De Lange-de Klerk, E. S. M. "Symphytum officinale (comfrey) ointment relieves pain and swelling after ankle distortion" Focus Altern Complement Ther 10 (2005): 24-25.