Pruning is essential in gardening to maintain the health and structure of trees and shrubs. It involves both skillful cutting and an understanding of plant biology for effective results.
Understanding Growth Buds and Apical Dominance: Plants primarily grow from the terminal or apical bud, which suppresses the growth of lateral buds. This dominance varies by species and affects the number and length of lateral shoots. The orientation of branches influences apical dominance. Vertical branches have strong apical dominance with vigorous growth near the terminal bud. Lateral branches at a 45° to 60° angle show reduced apical dominance, leading to more lateral growth. Horizontal branches lose apical dominance completely and often result in water sprouts.
Removing Heavy Branches: To remove large branches, start with an undercut or relief cut to prevent bark tearing. Then make an overcut or final cut outside the first cut to remove the branch. Finally, cut close to the branch collar to avoid damage and ensure optimal healing.
General Pruning Process: The best time for pruning is during the dormant phase in winter or early spring. Flowering shrubs should be pruned after blooming to avoid damaging next season’s buds. Evergreen shrubs should be pruned in spring. Fruit trees should be pruned to open up the crown, allowing more light to penetrate and promoting fruit production.
Pruning Roses: Prune back to healthy, live wood just above an outward-facing bud in the spring.
Pruning Techniques: Thinning: Removes entire shoots back to their base, encouraging growth at undisturbed shoot tips. Remove water sprouts and suckers to avoid energy loss and direct growth. Renewal Pruning: Aims to improve air circulation and light penetration. Older trees benefit from pruning to stimulate new growth. Crotches and Angles: Remove branches with narrow angles as they are weaker and more prone to damage. Healing and Regrowth: Pruning stimulates healing, which begins in the cambium layer. For faster healing, cut close to the main branch without injuring the bark ridge or branch collar. Pruning also stimulates growth near the cut site. Heavier pruning leads to stronger regrowth as the plant tries to restore balance between the above-ground and below-ground mass.
In summary, pruning trees and shrubs is not just about cutting back growth but also understanding the biology and growth patterns of the plant. Proper pruning promotes healthy growth, improves the plant’s aesthetic appearance, and prevents disease and damage.