How to take root cuttings

When to take root cuttings

Winter is the perfect time to propagate flowering perennials by root cuttings, an often overlooked technique that involves removing lengths of root from under the soil, which are then inserted into pots of compost to form roots and shoots. This method can be carried out anytime between November and late February, while plants are still dormant.

Suitable plants for root cuttings

Among perennials that will regenerate easily from root cuttings are Oriental poppies, Japanese anemone, acanthus, Anchusa azurea, brunnera, crambe, eryngium, drumstick primrose, phlox, verbascum, pasque flower and several types of hardy geranium, including Geranium pratense and Geranium sanguineum.

How to take root cuttings

Carefully lift a clump with a fork and sever a few long roots as close to the crown as possible – choose only those that are white, healthy and about pencil thickness. Replant the perennial immediately to prevent a check to its growth. If a perennial is in a pot, simply decant and select some roots from around the outside of the root ball.

Divide the root into 5cm long pieces with secateurs or a sharp knife. It’s important that cuttings go the right way up, so they are orientated in the same way as when attached to the parent plant. Either lay the pieces in front of you keeping the tops uppermost or make a horizontal cut at the top of the cutting with a slanting cut at the bottom.

Fill a 7.5cm pot with seed and cuttings compost. Make five vertical holes with a dibber and push a cutting into each. When the top of each cutting is level with the surface of the compost, cover with a thin layer of horticultural grit. Label and water.

Phlox, drumstick primula and other plants with finer roots need different treatment. As they’re too flexible to be pushed upright into compost, place 5cm long pieces horizontally on the surface of 12.5cm pots of compost. Arrange cuttings 4cm apart and cover with grit.

Root cutting aftercare

Place pots in a greenhouse, unheated porch or a cold frame. If you don’t have one, improvise by putting them next to a sheltered wall of your house, where the eaves will give some protection against excessive rainfall.

Shoots should appear within a few weeks, before the cutting produces roots. When roots eventually appear through the drainage holes in the base, carefully split up the root ball of cuttings and give each young plant its own pot filled with multi-purpose compost. Plants will grow quickly and should be ready for planting in the garden by summer.