Pruning instructions advise making an angled cut on stems. The angle applies more to the horizon or ground rather than the stem. The reason for this is that the interior tissue of stems and branches is softer than external tissue and the internal tissue shrinks to form a bowl shape that will collect moisture where disease pathogens can breed, unless the angle of the cut allows the moisture to drain away. On vertical stems, the angled cut would be similar to the diagrams below but, on a stem that grows at an angle, the cut can be horizontal to the stem if it allows better drainage of the stem interior. Pruning cuts on stems that produce alternating growth buds are always made above an outward facing bud. On stems that produce two growth buds at a stem joint, pruning cuts are positioned as shown in the diagrams below.
When pruning, position the secateurs (or loppers) so that the cutting blade is closest to the plant. This will avoid bruising the cut. After the Full Moon is a good time for winter pruning. When pruning after spring flowering, First Quarter phase is best to encourage fast regrowth.
How high to cut?
When pruning in winter, growth buds and “eyes” are often quite small and it is easy to prune too close to the selected growth bud, which will prevent sap flow to the bud as scar tissue forms. Plant sap and growth hormones are then directed to the next lowest bud, which will often point in the opposite direction – spoiling the shape of the plant. A good general rule is to make the bottom of the cut not lower than three quarters of the width of the stem you are pruning (See diagram, above). This will allow enough room for scar tissue to form and strong growth from the bud area.