‘Knitbone’, ‘bruisewort’, ‘boneset’ and ‘knit back’; these are just some of the folk names given to Comfrey, hinting at its long history as a medicinal herb. It was widely used to promote the healing of wounds and fractures, hence its common name, which is a corruption of the Latin ‘con firma’, alluding to the plant’s ability to knit bones back together. The botanical name Symphytum derives from the Greek word for ‘unite’. The leaves contain allantoin, a substance which can help tissue, bones and cartilage to grow. These were ground up and made into a poultice for wounds, while the roots were also grated to make a sludgy material used to pack around broken limbs.
The leaves have also traditionally been infused to make tea, or boiled and served as a wilted green vegetable. Today, although there is much debate about the safety of ingesting the plant, Comfrey ‘tea’ is still widely used by gardeners as a fertiliser, due to the success of its extensive root system in ‘mining’ the soil for nutrients and minerals. In particular its foliage is rich in potassium. (See http://permaculturenews.org/2010/10/01/the-wonderful-multi-purpose-comfrey-plant/).
Most books say the first blooms on Comfrey – a member of the Borage family – appear in April, but here on the South Coast it is already coming into flower. I am excited to have several plants in our new garden and think the bell-shaped creamy white flowers very attractive, even more so because of Comfrey’s beneficial properties. Not everyone is a fan, though. In her book Wild Flowers, Sarah Raven reveals that she regrets introducing Comfrey to her herb garden as it can quickly become invasive on heavy soil. There is a cultivar of Russian Comfrey (Symphytum x uplandicum) called Bocking 14 which is sterile and therefore does not set seed which has become popular to prevent such invasion. On our chalk soil, the common Comfrey (Symphytum officinale) does not seem to have spread much since last year.
Mature Comfrey plants can be cut several times during the growing season and added in small amounts to the compost heap or used to make a liquid manure high in potash.
To make Comfrey ‘tea’ (for feeding plants not people):
- Cut the leaves with shears and chop coarsely into a bucket or container.
- Steep in water, placing bricks or another heavy item on top and leave for several weeks until they form a dark liquid.
- Dilute by about 15:1 before using as a liquid fertiliser.