How to take root cuttings

Taking root cuttings is an easy way to propagate herbaceous perennials – and now (late autumn or early winter) is the ideal time to do it as the plant is dormant. This method works well for plants that tend to produce suckers from their roots naturally, many of which have thick, fleshy roots. So, it is a good way of propagating Acanthus mollis, Phlox paniculata, Primula denticulata and oriental poppies for example. This is the method I use to prepare root cuttings from Acanthus mollis; it couldn't be simpler:

Lift a vigorous plant (I often try and take root cuttings from suitable plants when I buy them, i.e. before planting in the garden!). Clean the soil off the roots. Aim to remove no more than a third of a plant's roots and replant the parent plant as soon as possible.

STAGE 1
Cut off young roots close to the crown of the plant. The roots should be, ideally, at least as thick as a pencil (I have had some success using thinner root material but use longer lengths).

STAGE 2

Cut the roots into about 5cm lengths.

To make sure that you plant the cuttings the right way up, cut the bottom of each cutting at an angle and cut the top straight across. 

STAGE 3

Insert the cuttings vertically, angled end down, into gritty compost with the top of each cutting level with the surface of the compost. (Thinner cuttings should be laid horizontally on the surface, about 2.5cm apart, then covered with 1cm of compost).

STAGE 4

Then add a layer of grit about 1cm thick.

Place in a cold frame or sheltered place and water lightly. Do not allow to dry out.

STAGE 5

There should be signs of new growth by the following spring when the cuttings can be individually potted up and grown on until they are big enough to plant out.