What is pollarding?

Pollarding from RHS article ‘Gardening For All’
 

 

 
Pollarding is a method of pruning that keeps trees and shrubs smaller than they would naturally grow. It is normally started once a tree or shrub reaches a certain height, and annual pollarding will restrict the plant to that height.
 
Pollarding is a pruning technique used for many reasons, including:
  • Preventing trees and shrubs outgrowing their allotted space.
  • Pollarding can reduce the shade cast by a tree.
  • May be necessary on street trees to prevent electric wires and streetlights being obstructed.
 
When to pollard 
The best time for pollarding many trees and shrubs is in late winter or early spring. However, bear in mind the following:
  • The least favourable time for pollarding is the autumn, as decay fungi may enter the pruning cuts
 
Maintaining a pollard
Once a tree or shrub is pollarded, continue the annual cycle of cutting.
 
  • Branches should be pruned just above the previous pollarding cuts.
  • In some cases, such as where some leaf cover is required, leave some branches intact or cut back to a side branch.
 
Rejuvenating an overgrown pollarded tree
Seek advice from an arborist before doing any work. Although having a tree pollarded regularly is expensive, an overgrown pollard may require more surgery to remove larger parts of the tree at a greater height.
 
  • Horse chestnut (Aesculus x hippocastanum) needs to be cut to a higher point in the tree, rather than to the original pollards. This avoids exposing large amounts of old wood, but creates a second set of pollard heads.
 
After any major work, the tree should be monitored for any further maintenance required.
 
Problems 
Trees with weaker wood prone to producing multiple shoots, such as poplar (Populus) and willow (Salix) can become hazardous. Some of the weakly-attached branches can break off and fall to the ground. Ideally, try to return to a frequent cutting cycle and have an arborist carry out a safety check regularly.
 
A similar problem can occur with trees such as beech (Fagus sylvatica), oak (Quercus robur) and sweet chestnut (Castanea sativa). The branches become heavy when pollarding lapses for several decades, and these may break away in windy weather. Consult an arborist, if you are in any doubt.