In the latter form old trees, the summer pruning of which has been neglected, are apt to acquire an undue projection from the wall and become scraggy, to avoid which a portion of the old spurs should be cut out annually.
The summer pruning of established wall or espalier-rail trees consists chiefly in the timely displacing, shortening back, or rubbing off of the superfluous shoots, so that the winter pruning, in horizontal training, is little more than adjusting the leading shoots and thinning out the spurs, which should be kept close to the wall and allowed to retain but two or at most three buds.
They may be produced, by taking care, during the summer pruning or disbudding, to preserve a number of the little shoots emitted by the yearly wood, only pinching off the minute succulent points.
Winter pruning is effected when the tree is comparatively at rest, and is therefore less liable to " bleeding " or outpouring of sap. Summer pruning or pinching off the tips of such of the younger shoots as are not required for the extension of the tree, when not carried to too great an extent, is preferable to the coarser more reckless style of pruning.
But summer pruning has been much extended since the introduction of restricted growth and the use of dwarfing stocks.
