Comfrey is a perennial herb native to Europe in the Boraginaceae family that can grow up to 5ft in height. It’s recognizable with its large, hairy broad leaves, hollow, bristly stem, black tuberous root, and small light purple to cream bell-shaped flowers. It’s often found in damp, grassy places, such as riverbanks and ditches. The roots should be harvested in the spring or autumn. Comfrey can be grown from seed, but it’s easiest to grow comfrey from root cuttings. It does best in full sun to part shade in well drained soils, and is prone to vigorous spreading. This versatile herb high in calcium, potassium, and phosphorous is useful both medicinally and as a fertilizer in the garden.
Medicinally, both the root and leaf are used for their vulnerary, demulcent, astringent, and expectorant actions. Comfrey contains a constituent called allantoin which speeds the healing of wounds and minor skin irritations. In combination with it’s demulcent properties, comfrey leaf serves as a very healing herb for ulcerative colitis, hernias, and gastric and duodenal ulcers and when taken internally. Its astringent properties are healing for mild internal hemorrhaging. It has also been used to treat bronchitis and irritable coughs, as it aids in expelling mucus as it soothes the inflamed lung tissue. It also makes a good gargle for sore throats and hoarseness. The root is used more often as a nutritive and rejuvenating tonic for the lungs and mucus membranes, where as the leaves are more astringent and anti-inflammatory. It combines well with ginger, cloves, and cardamom for expectorant actions, and as a lung tonic, combines well with elecampane. For pitta and vatta, comfrey is a regenerative for the body, mind, and prevents decay.
External Medicinal Uses
Externally, comfrey root and leaf can be used in salves, compresses, and liniments for healing cuts, scrapes, ulcers, burns, and preventing scarring. It not only accelerates healing, but conditions and soothes the skin. However, with deeper wounds, comfrey should not be used until the wound has healed further, as comfrey’s quick healing nature can cause the surface skin to heal quickly over the deep wound, which can lead to an abscess. Comfrey leaf can be used as a hot compress for bronchitis and other lung complaints, as well as sore joints and pulled tendons. In traditional midwifery in Mexico, comfrey compresses are applied to torn vaginal tissues. Some bath recipes call for adding comfrey to promote “more youthful looking skin”.
Whether or not comfrey is safe for internal use is an ongoing source of controversy. Comfrey contains a chemical constituents called pyrrolizidine alkaloids, which if consumed in large amounts can damage the liver. In tests, animals fed these constituents either showed signs of poisoning or died, and there have been several human cases of poisoning after prolonged consumption of comfrey. Pyrrolizidine alkaloids are found in higher concentration in the root of the plant than it is in the leaves, and despite claims that the alkaloids are not water soluble therefore safe to drink as a tea, FDA studies have found them present in water-based infusions. Many herbalists recommend that comfrey only be used externally, but at the same time, there are many that still use comfrey internally, choosing personal experience and thousands of years of historical use over this research. I’d say this is up to you individually whether or not to use comfrey internally. I stay away from taking the roots internally, however, I feel that a pinch of comfrey leaf in an infusion for certain conditions here or there is safe to drink.
A decoction of 1-3 teaspoons of dried root per cup of water, simmered for 10-15 minutes, drunk three times daily. Similarly, 1-3 teaspoon of dried leaf per cup of water, infused for 10-15 minutes, or 2-4ml of the tincture.
Comfrey as Fertilizer
The deep roots of comfrey bring nutrients up from the soil, depositing them in the leaves. This produces leaves heavy with vital minerals and nutrients for your plants. Using comfrey as mulch or adding comfrey leaves to your compost makes for a more nutritious compost, and encourages the pile to heat up, speeding up the composting process. You can alternate layers of comfrey, organic material from the kitchen, and carbon (twigs, hay, dead leaves), but be careful not to add too much comfrey of the compost will get thick and sludgy. You can also make a liquid fertilizer quick and easy with comfrey leaves that works great for fruits, flowers, and vegetables. Nettles can be added to either recipe for an additional nutrient boost.
1. Stack dry leaves in the bottom of a bucket
2. Weight the leaves down with a stone or a brick, then fill the bucket with water.
3. Let stand 3-5 weeks, and then apply to your garden.
1. Get two buckets, and drill holes in the bottom of one of them. Stack the bucket with holes inside the bucket without holes.
2. Place the dry comfrey leaves in the bottom of the bucket and weight them down with a stone or brick
3. As the comfrey decomposes without water, a thick black concentrate drips down into the second bucket.
4. Collect the concentrate and store sealed tightly. Dilute 15:1 before using.
Both mixtures smell awful (“what died?” kind of awful), so be sure to store them outside with a tightly fitting lid.
An important note about comfrey as a fertilizer: While nitrogen encourages leaf growth, excess potassium can slightly stunt growth and make leaves coarser. However potassium also promotes developing flowers and fruit, so it is best to apply comfrey fertilizer after the first flowers have set to let the leaves develop as needed and support the fruit/seeds/flower growth. For reference, comfrey has a N-P-K (Nitrogen, Phosphate, Potassium) ratio of 1.8 – 0.5 – 5.3.
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