The restorative pruning of older shrubs and trees is a three year process that requires a well thought out plan for execution. Knowing the species of your plant and its growth and flowering habit is essential. There is a right time of the year for pruning and that can vary from plant to plant. A lot depends on the desired outcome of your plan, such as, shaping and altering the natural growth into an unusual form, reducing the size, restoring vigor and health or improving fruit and flower production. Whatever your plan entails, know that the act of pruning correctly will bring great benefits to the plant.
It is important to understand the healing process in restorative pruning. Woody plants heal by forming rolls of callus over the wound. The callus is the plant’s way of walling off or compartmentalizing the damaged tissue from the healthy wood. The best pruning time to facilitate the best wound healing is just prior to the onset of growth in Spring (March-April) or just after maximum leaf expansion in early to mid June. Winter and Summer pruning should be minimal so as to prevent suckering, die-back and desiccation which are all problems brought on by poor timing of pruning. Knowing your plant is the best advice. Also, before pruning it is imperative that your pruning tools are sharpened and sterilized. A sharp cut prevents bark and cambium tearing and sterilization prevents transference of disease.
Rejuvenation of older shrubs starts each year with removal of dead or damaged branches. This “cleaning” allows the pruner to see the plant frame without unwanted debris. Also, each year no more than one third of the living plant material should be removed. Too much removal at one time stresses the plant’s ability to produce enough food (photosynthetic surface area) for the root system and for the following year’s growth and leaf/flower/fruit production. The first year’s cuts should be focused at the center of the plant and at the crown, taking out several of the oldest, unproductive branches. This makes room for light to get into the densest area of the plant, allowing for new center shoots to develop. The proper cut is always made immediately above an outward facing bud node where a new leaf is ready to develop. The plant will send hormones to the tip end readying for the new stem leader to grow. If height reduction is needed follow a “1, 2, 3 step” stem reduction. This is cutting at three different heights (low, medium and high) so that the plant has a more natural look. Crossing, rubbing, inward growing branches or those that detract from the natural form of the plant should be removed. Fertilization in the Fall before the Spring pruning will help prepare the plant for a better Spring healing wound time. However, if you have not fertilized in the Fall do so immediately following the Spring pruning. The plant’s health hinges on proper horticultural procedures for the best outcome, such as the Fall or Spring fertilization, watering, mulching and insect and disease control.
In the second and third year continue to select and remove the branches as described above, so as to allow the original form to begin to be restored. This three year process will, in the long run, increase the longevity of the plant and its ability to function as it naturally should. The overall beauty of the plant is the final outcome of your hard work.
“Let There Be Light”