Root cuttings are a means of increasing plants that naturally send up shoots from that are damaged.
This can be a curse in the garden, as anyone who has tried to remove acanthus from a planting scheme or who grows the attractive but spreading Rhus (sumach) knows all too well. We can turn it to our advantage in growing desirable perennials such as paeonies, dicentra (bleeding heart), romneya (Californian tree poppy), poppies (papaver), crambe and aconitum (monkshood), as well as woody plants like rubus and spirea, to name a few.
Take Root Cuttings in Winter Root cuttings are taken while plants are dormant; that is, in late winter or very early spring for most plants.
Lift the entire shrub or, for larger shrubs, unearth a section of the roots. Using clean, sharp secateurs or loppers, cut off sections of the root close to the main root stem.
Perennials are lifted out of the ground, suing a garden fork, and a section of the root cut away close to the main root stem.
To reduce the risk of introducing disease not only to the new plants but also the parent, use a clean sharp knife or secateurs.
Preparing the Cuttings Cut the root section in segments 4cm (1.5in) or so long, again, using a clean sharp knife or secateurs. Use a straight cut across the top and angle the cut at the base of the cutting, so that you will know which end is ‘up’.
Fill 12cm (5in) pots to just below the rim with a sterile potting mix, tamped down to reduce settling. Make planting holes the same depth as the length of the cuttings, using a dibber. Insert the root cuttings, straight cut end ‘up’, into the holes and leave level with the top of the soil.
Cover with a light, thin layer of sand and water with a fine spray.
Fibrous rooted perennials Fibrous rooted perennials, such as phlox, can be propagated from root cuttings, although the method differs slightly. Sections of root 5cm (2in) long are cut and laid on the soil surface in a pot, covered with a thin layer of sand or potting compost.
Aftercare Keep root cuttings in the glasshouse or cold frame throughout winter. Separate and re-plant individual plants into their own small pot in spring after leaves have begun to develop.
Well-grown, strong plants should have developed by autumn, ready for planting into the garden.The new plant is identical to the parent, enabling special forms to be reproduced.
Using Nature Propagating using root cuttings is simply using nature to increase our plant stock, or to keep tender plants in our gardens. And it's a whole lot of fun besides.
Paeonies are excellent candidates for root cuttings
Resources for Taking Cuttings
Garden fork
Secateurs and/or knife - ensure they are clean and sharp
Pots, 12-15 cm in diameter
Sterile potting mix
Dibber, or pencil
Spray can for misting
Optional
Root promoting hormone
Sand
Romneya coulteri, the Californian Tree Poppy
All-Important Hygiene
To reduce the risk of moulds and fungi attacking newly propagated plants strict hygiene regime is essential.
Select cuttings only from healthy, disease-free plants
Use new pots or clean used pots thoroughly, scrubbing inside and out to remove soil residues and other matter. Jeyes fluid is an effective disinfectant – follow the directions.
Use a sterile potting mix of propagating compost. Never re-use compost when propagating as this allows disease and pests to attack your new plants.
Ensure covers and heated propagators are clean and disease free
Maintain good air circulation to prevent mould build-up
Dicentra spectabilis, Bleeding Heart, can be increased from root cuttings
