When pruning a tree for shade it is prudent to follow this advice:
- Only prune very young shoots which cicatrize well in 2 or 3 years,
- Respect the equilibrium of the shape of the tree
- Prune at the correct time at the beginning of the spring for best cicatrization (which is not the case in the winter)
The pruning for shape which has been started by the nurseryman must sometimes be prolonged for a short period of 2 to 5 years depending of the height of the parasol required. Do not take into account the type of flowering.
Prune the prolongations of the branches, the branches close to the centre of the central axis, if this has not already been done, to encourage the development of the external branches which will form a "parasol". Cut back about a third of the length of the branches to encourage the development of numerous starting points which will then serve to "open out the parasol".
The following years continue to give priority to the lateral branches and remove branches which reach upwards to the sky. Cut out where possible the starting points while respecting the general shape of the tree. Prune the lateral branches more or less severely depending on space available. When the available space is very limited, one can cut off all the shoots of the year.
If the foliage is listless keep 1 or 2 high branches to draw the sap upwards and re-launch vigor. Maintain proportional development of lateral branches, or even hanging branches in view of the regularity of the shape. Cut superfluous or badly placed foliage which unbalances the tree. Cut off branches that are too low or annoying to leave enough room for a lounger...
Attention: A bad pruning is often more harmful to trees than having no maintenance, avoid taking off more than 15% of the height each year.