Once your comfrey plants are established, you can easily propagate more plants by taking root cuttings or crown cuttings (offsets or sets).
Almost any root fragment of comfrey has the potential to take root and become a new plant, this is why is it important to take extreme care when splitting comfrey, or when taking cuttings from your own plants. Unless you want a nursery bed of many plants to generate and harvest cuttings, take care not to drop any root fragments onto bare soil. Comfrey is a challenging plant to get rid of – if you do have comfrey growing where you don’t want it, see our guide to getting rid of comfrey.
Crown cuttings / offsets
Crown cuttings are the quickest and most reliable way to establish new comfrey plants. The best time to take crown cuttings from your mature plants is March or April – there will be an abundance of new shoots, and a full growing season ahead for your new plants to establish.
Decide how many new plants you wish to raise, and slice horizontally through the plant at a depth of about 3 inches with a sharp spade or with a knife to remove a segment of the crown. This segment can then be divided into offsets, each with some root material and one or more growing tips. The mature plant will recover quickly providing you don’t remove the entire crown. If you do, expect new shoots to emerge within 4-6 weeks, and the plant to fully recover by the next spring.
Then follow our guide to growing comfrey from crown cuttings – by the end of the growing season your new plants should be thriving, and you may be able to take a small harvest.
If your existing plants are young (less than 2 years), or you want to raise many new plants, root cuttings may be a better option. Growing comfrey from root cuttings is almost as reliable as from crown cuttings if approached carefully (we achieve around a 99% success rate), the main downside is that the plants will be about 8-12 weeks behind those raised from crown cuttings during the first year of growing.
Roots are most easily harvested by driving a sharp spade vertically down through the edge of the crown, slicing off a one or more growing tips. These should be attached to deep roots, which with care can be removed in a single piece.
Depending on the age of the plant these roots may be up to 24 inches in length, and 3-4 inches in diameter.
Cut the roots into 1-2 inch pieces – 1 inch for thicker roots, 2 inches for thinner roots.
Then follow our guide to growing comfrey from root cuttings – by the end of the growing season your new plants should be growing strongly, and should produce a small crop from the following early summer.
Splitting comfrey plants
If you have a mature plant and only want one additional plant, comfrey splits very easily. Drive a sharp spade vertically through the centre of the plant to separate between one third and one half, lift and plant. Be careful to match the soil line, or plant slightly deeper.
The split comfrey will establish very quickly, and catch up with the source plant within a year.