Friday, June 9, 2000
Tree Talk: When to prune?
A common question regarding tree pruning is when. The how, why and what to prune questions seem to be of secondary concern. Surprisingly, most experts respond with now.
So why then is timing thought to be so important to pruning? Well, there are certainly plenty of factors cited in the literature influencing flower displays, growth and overall health to confuse anyone. Some trees, such as crabapples, set flower buds a year in advance - prune right after flowering. Pruning dormant trees saves the energy used to make leaves, crucial for maximum growth (if wanted) and disease resistance. Over-stimulation can result from spring pruning making the tree vulnerable to disease. Fungal spores that attack tree wounds are most active in early fall. Giving trees time to heal before winter helps avoid desiccation at the wounds. Tree bark tends to tear in the spring if you're not careful. Some trees such as maple, birch and pine sometimes bleed excessively in the early spring, which can be unsightly and invite infection.
Conclusion? Basically trees are better off with light live-wood pruning and complete deadwood pruning done any time you're in the mood, than with the best intentions to prune while the tree (and you) are in dormancy. Just make sure to prune when the weather is nice and dry; it's certainly more pleasant and it frustrates the evil fungi and bacteria lurking out there.
John Bakewell of Rutland Street is an arborist.
© 2000 The Carlisle Mosquito