Coppicing

Coppicing is a means of plant manipulation. The practice involves the complete removal of the canopy of woody plants, cutting them at or just above ground level. 
We asked Michael Looker about the technique.

Why would gardeners want to coppice plants?

Coppicing can be used for a variety of purposes. Some plants have very attractive juvenile foliage - eucalypts such as Eucalyptus gunnii and E. perriniana for example - and coppicing allows that foliage to be displayed over a long period. It also means this foliage can be harvested e.g. for the cut flower trade.

Other plants e.g. Cornus alba `Sibirica' and Salix irrorata produce attractively coloured winter bark on newly regenerated wood after severe pruning or coppicing.

Coppicing can also be used to produce a supply of juvenile plant material for propagation and is especially used for the propagation of clonal rootstock in fruit tree production.

Some mature shrubs can be cut back to ground level to regenerate them. This is much more cost efficient than removal and replanting. Species that will respond well to this treatment include Sparmannia africana, Escallonia rubra, Thryptomene saxicola and Calothamnus quadrifidus (See right.)

I am particularly interested in how the technique can be used to manipulate woody ground cover plants, especially in public open space plantings. This technique is used extensively overseas, but there hasn’t been a great deal of research done on it here, especially as far as using Australian plants is concerned. It has great potential as an inexpensive alternative to removal and replacement of ground cover plantings.

Which plants are the most suitable for this treatment?

Some plants are not suitable at all and suitability varies within genera and also between different provenances of the same species. As a general rule, species which are most suitable are those that contain dormant buds, lignotubers, basal burls or readily release dormant buds into growth after apical dominance is removed. Many Australian plants are very suitable because they have evolved to survive the effects of canopy removal, especially by fire.

How should coppicing be done?

On suitable species the entire canopy should be removed, cutting the stems to just above ground level.

Public open space trials indicate that, with suitable species, a flail mower is an effective and efficient way of removing the canopies on large plantings.

Overseas, coppicing to rejuvenate some species of woody ground cover plants is a well-established practice. One very successful technique involves cutting the plants right back to 100mm from ground level, chipping them on the spot and returning the mulch immediately to the area. This helps prevent weed invasion while the canopy is removed and helps make the area look more acceptable in the bare phase. An appropriate fertilising regime may need to accompany this practice.

When should coppicing be carried out?

Trials at La Trobe University with Coprosma x kirkii indicated that there was no difference in rejuvenation following cutting at different times of the year. However other research indicates that with some species, the time of cutting affects how well the plants respond. With some deciduous species in particular, cutting in early summer reduces sprouting because carbohydrate levels have been depleted by spring growth. While the timing may not matter with some species, as a general rule, choosing a time before active growth rather after it, is a sensible practice. The best time varies from species to species.

How often can coppicing be done and does it shorten the lifespan of the plant?

Once again this varies from species to species. Research indicates that generally plants do not respond well if they are too young or if they are too old. Also if coppicing is done too often, plants will generally become depleted in vigour and may die.

At La Trobe, Grevillea `White Wings' is planted widely to provide a massed shrubbing and ground cover. This cultivar responds quickly to heavy pruning and shrubs pruned to 300mm from the ground reach up to a metre within three months following pruning. Grevillea curviloba has responded similarly to Grevillea `White Wings' and both are regularly cut back every two to three years.

What are the advantages of coppicing as a plant management technique?

Coppicing represents a very cost effective means of rejuvenating plants. Because the root systems are already established recovery and rejuvenation are swift. In public open spaces this technique requires very little in the way of resources, provided that appropriate species have been selected in the first place. Apart from the cost and labour aspects, coppicing is much better than removing and replanting plants which disturbs the soil and encourages weeds.

-oOo-

Michael Looker is a Senior Lecturer in Environmental Horticulture at Burnley College, Institute of Land and Food Resources, The University of Melbourne. His career has included time at Kew Gardens in UK and the Royal Botanic Gardens, Melbourne.

*******************

 Copyright protected - refer all copyright enquiries to Global Garden 
Global Garden http://www.global-garden.com.au

    RETURN TO GLOBAL GARDEN HOME PAGE