Coppicing, which
is also known as stooling, is the centuries-old technique
of cutting shrubs and trees to ground level to encourage new
shoots. For gardeners, it is particularly useful to promote
colourful juvenile stems, ornamental foliage and to rejuvenate
plants that tolerate hard pruning.
Dogwoods,
including Cornus alba , and willows, such as Salix
alba var. vitellina 'Britzensis', are prized
for their vibrant young stems. The best colour comes from
the one- or two-year-old wood. To ensure a continuous supply,
it is necessary to shorten all the stems to within 5-7.5cm (2-3in)
of the ground or to the previous year's stubs in late winter or early spring each year.
Some Cornus, such as 'Midwinter Fire', can be weak growers on poor soils. If this is the case, cut out just one third of the growth each year. The stems will not be as richly coloured, but they will be stronger.
Coppicing to a stump about 60cm (2ft) tall in early spring can have dramatic effects on other plants. It restricts the size of trees such as Paulownia and Catalpa. Instead, all the plant's energy goes into a burst of rapid growth in early summer to produce a cluster of stems and, as an attractive side effect, causes the leaves to grow larger than usual. A similar treatment of Eucalyptus gunnii encourages bluish, juvenile foliage that is considered more striking than the adult leaves.
Finally, overgrown yews, hazels and hornbeams can be cut close to the ground with a pruning saw in late winter. It results in the production of lots of new stems that can be thinned to make an airy bush once again. Hazels, in particular, are coppiced every few years to produce straight canes that can be used as supports in the garden.
Pollarding is a very similar process, but stems are pruned back to a trunk or leg.