I am determined to eat an apple from my garden this year. Last year, my resident squirrel took a single bite out of every one, decided none were to his favour and threw them on the ground. I tried netting the tree, but he found a way in. The squirrel gets into my apple trees by leaping from another, so this year I am going to judiciously prune his springboard.
It’s actually not a bad time to do a little pruning. It is a bit of a myth that trees should only be pruned in winter. Many actually benefit from summer pruning; a tree in full swing heals quicker. It is also easier to see what impact you are making when they are in full leaf.
I am going to crown lift my magnolia (the squirrel’s launch pad), which means I will remove the lower branches to raise the crown of the tree. This is one of the simplest tricks. It lets in light and extends the view once blocked by the lower branches. As with winter pruning, you should start by removing anything diseased. It used to be said that you should also remove anything dead or dying, but unless it is dangerous, it’s better to leave this material for insects that live in it.
The rule with summer pruning is wait until after flowering. Spring-flowering trees such as Amelanchier, Cercis, flowering dogwoods (Cornus), cotoneaster, hawthorns (Crataegus), Deutzia, Forsythia, Kalmia latifolia, Ligustrum, magnolia, ornamental apples (Malus), flowering cherries (Prunus), Spiraea, Sorbus, Styrax japonica and Philadelphus can all be pruned over the summer. Flower buds on these plants develop in the previous season’s growth, so the flower that bloomed this spring developed last winter as a bud.
If you want to do major renovation work, it is still better to wait until winter. Summer pruning is about removing a little bit here or there, whether to improve the view, stop a branch damaging a property or irritate a squirrel.
Conversely, anything that flowers later in the summer should be pruned before spring growth begins. So you will have to wait until next year for Glossy Abelia (Abelia x grandiflora); butterfly bush (Buddleia davidii) and several species of Albizia, hydrangea, Rhus, Stewartia and Symphoricarpus.
Finally, opinion is shifting on applying tree paint after pruning, which is said to aid the healing of pruning cuts. The evidence shows that it may not be that useful and could in fact harbour disease. A healthy tree will quickly callus over any wounds of its own accord.