How to Propagate Plants Using Root Cuttings

Root cuttings are one of the lesser-known propagation techniques, yet for the right plants they are remarkably reliable and require almost no equipment. You work entirely underground, taking sections of fleshy root in late autumn or winter when the plant is dormant, and each section generates a new shoot in spring. Plants that produce extensive root systems and sucker freely are the best candidates — think oriental poppies, acanthus, Japanese anemone, phlox, verbascum, and echinops.

When to Take Root Cuttings

Timing is critical. Root cuttings are taken when the plant is fully dormant and the roots are full of stored nutrients — late autumn through to late winter. This is also when the soil is most accessible without seriously disturbing active growth. Avoid taking cuttings in spring when stored nutrients are already being mobilised into new shoots, as the root sections will have little energy reserves left and fail rate rises sharply.

How to Take and Prepare Root Cuttings

Dig carefully at the edge of the plant to expose thick, pencil-sized roots without severing the main crown. Cut sections 5–7 cm long from thick roots (for large-rooted species like acanthus) or 3–5 cm from thinner-rooted plants (like phlox). Always make the top cut straight across and the bottom cut at an angle — this tells you which end is up when you plant. Rinse the cuttings in clean water and dust lightly with fungicide powder if you have seen root rot before.

Planting the Cuttings

For thick cuttings, insert them vertically into pots or a prepared nursery bed with the flat-topped end just at or just below the surface. Thin root cuttings can be laid horizontally 3–4 cm deep in trays of gritty compost. Cover with a thin layer of grit to prevent surface capping and label everything clearly. Place in a cold frame or unheated greenhouse. No heat, humidity tent, or rooting hormone is needed — dormant root sections are self-sufficient through winter.

Spring Emergence and Potting On

By mid-spring, shoot tips will push through the soil surface. At this point, roots are well established below. Pot cuttings individually into 9 cm pots of peat-free compost and grow on in a sheltered spot. Young plants from root cuttings are often vigorous and can reach planting-out size surprisingly quickly. They can generally be planted in their permanent positions by late summer of the same year, giving a full growing season to establish before their first winter.