Cultivating root cuttings is a reliable, cost-effective method of growing comfrey Bocking 14. They can take up to 40 days to properly take, so crown cuttings may be a better option if you want to accelerate production.
Root cuttings (or root-sets) are sections of comfrey root usually 1-2 inches long, and at least 10mm in diameter. Almost any comfrey root fragment, however small, can take root and grow into a healthy plant, but this is the minimum size for reliable results, especially when sending cuttings by post.
Our standard comfrey root cuttings pack contains 8 roots, with an average weight-per-root of 10g.
Depending on the diameter of the harvested root, your cutting may also be split vertically – this will not affect the viability of the cutting, but does give you the option of planting horizontally and producing multiple plants from one root cutting (see below).
You have two options for growing from root cuttings: bringing on in pots then planting out or into larger pots once estalished, or planting directly into permanent beds. We highly recommend the first option if at all possible – it’s more reliable, since you can more easily control factors such as moisture, pests, and biosecurity.
Bringing on in pots
- You’ll need one pot per cutting. Pots should be at least 3 inches in diameter, with at least 4 inches of depth, and ideally 6 inches.
- Fill pots with a mixture of soil and compost. As they grow your plants will benefit from a nitrogen feed of some kind, so adding in a small amount of growmore or other nitrogen-release fertiliser at this stage is fine.
- Plant root cuttings about half and inch below the surface.
If the cutting is split horizontally, you can plant with the cut surface facing upwards to produce multiple small shoots from a single cutting.
If there are any buds or other shoots on the cutting, make sure they are pointing upwards.
- In autumn and spring, keep pots frost-free – ideally in a greenhouse or polytunnel, or on a window-sill. In summer, pots can be kept outside, but beware them becoming water-logged in poor weather, which will check the growth or even kill the comfrey.
- Water well when the surface of the pot is dry. Comfrey is very tolerant of both dry and wet conditions, but will grow best when the growing medium is kept moist.
- The cuttings will take up to 40 days to ‘take’, but can show new growth in as little as a week. Not all of your comfrey cuttings will take the same amount of time to take.
Be patient, and don’t disturb the cuttings in this period. If you see no growth after 40 days, carefully lift one of the cuttings and check for the presence of new, fine white roots. If you see none, please contact us – we offer free replacements for any cuttings that fail.
Once there is new growth, with at least two leaves fully opened, you have three options:
- Plant into larger pots to bring on further before planting out
- Plant out into permanent beds
- Plant into large pots as a permanent home