The golden rule of pruning is never to cut without good reason, and this prompts the fundamental question. What is the purpose of pruning? Depending on the type of plant and our expectations of it, pruning can be done for any of the following reasons:
- Controlling size. Most plants eventually grow too large for the available space. Wisteria, vines and climbing roses are examples that can soon become thugs in the garden (check size of mature plant before buying!!).
- Promoting good health. Plants are inevitably prone to all kinds of injuries, such as frost damage and diseases. Timely pruning can prevent mishap and infections from becoming serious.
- Maintaining youth and vigour. The predictable response of plants to pruning is more growth, and the harder they are cut back, the more vigorously they respond. In this way pruning can prolong a plant's life by constantly renewing its’ production of new, youthful stems.
- Forming early growth. Pruning shrubs, trees and climbers after planting and during their formative years helps to train a balanced framework of main stems and encourages branching that is easier to maintain.
- Deadheading. This is a type of routine pruning that diverts a plant's energy away from seed production into further flowering and growth.
- Removing unwanted growth. Sumachs, grafted lilacs and raspberries to name a few cases often produce suckers. These are surplus stems that grow away from the main plant. If not removed they can take over and weaken the main plant. Any reverted shoots on variegated shrubs should be cut out or all variegation will be lost.
- Creating shapes. Hedge trimming is one example of shaping by pruning, topiary is another. Many plants can be trained by pruning into ornamental or space saving forms e.g. Fruit fans, fuchsia and rose standards.
- Renovating neglect. Many neglected overgrown plants can be saved by rigorous cutting back at the right time to rejuvenate growth and allow you to start formative training once more.
Please do not go out and start pruning before you check with a good gardening book or the internet what kind of plant it is and the correct time of year to do it. Happy reading and pruning.