There are many reasons why trees might need pruning. These reasons could include improving the structure of the tree, to remove dangerous or defective branches; to reduce the shading from the canopy, the reduction of sail effect or to provide clearance between the tree and a structure – to name just a few. Care must be taken, however, if you prune too large a branch can lead to disease entering the tree via the wound/s left behind, or reduce the vitality of the tree due to excessive removal of foliage. The severity will vary from negligibly in lightly pruning small trees, to catastrophically when heavily pruning large trees.
The big question is when should the tree be pruned? Tree pruning should generally occur after the leaves have ‘flushed’ and hardened, so late spring through summer. There are some exceptions, however, as some species such as Birch, Walnut and Maples, will ‘bleed’ sap and risk losing valuable sugars in the process if pruned in early spring, therefore the pruning of these trees should be carried out when this risk is low i.e. summer or mid-winter.
Species belonging to the genus Prunus such as Cherry partially rely on the production of a resin or gum to aid in the defence against wound related pathogens, therefore pruning should occur in the summer. In general, pruning should avoid periods where the exposed wood will be left open to severe conditions such as drought, frost, and periods of fungal sporulation.
Training Young Trees
The age of a tree also plays a vital role in how you prune them. Young trees have different requirements than their older relatives. Pruning from a young age is quite beneficial to plants and is commonly known as formative pruning. It promotes healthy and balanced growth and also allows you to control the general shape in which it will grow into.
- Young evergreens do not require pruning while during their development.
- Young deciduous trees benefit greatly from formative pruning during the early stages of growth, as they produce a lot of shoots that spread in all directions.
- All young trees can benefit from the removal of overly long or sickly shoots, regardless of their type.
- It is much easier to correct lopsided growth through pruning while the plant is still young.
Regardless of how far we have progressed as a species and how much control we can exert over our environment, the fact remains that there is an innate rhythm present in nature. Working against this natural rhythm in your garden can have disastrous consequences as some plants may die or fail to produce fruit
Pruning is a task best carried out by arborists and professional tree surgeons, who will know how best to maximise the tree’s potential without compromising its vitality.
Please do not hesitate to contact Naturally Trees for your tree surgery needs, or even if you need some advice from a professional.
| Species | Tolerance to hard pruning Good, Fair or Poor | Optimum time to prune | Notes |
| Deciduous trees | |||
| Acacia | Fair | Spring (late) | Living wood most obvious, dead can be easily identified |
| Ailanthus | Fair | Spring (late) to summer | |
| Alder | Fair | Spring (late) to summer | |
| Apple | Good | Winter (mid) | Prune every year for fruit production |
| Ash | Fair | Spring (late) to summer | |
| Beech | Poor | Spring (late) to summer | |
| Birch | Poor | Summer or winter (mid) | Prone to bleeding |
| Cherry (& other Prunus sp. e.g. Almond, Apricot, Peach, Plum) and Silver leaf. Avoid fungal sporulation period (autumn) | Fair | Summer | Prone to drought, frost damage |
| Elm | Good | Spring (late) to summer | |
| Eucalyptus | Poor | Spring (late) to summer | |
| Hornbeam | Poor | Spring (late) to summer | |
| Horse Chestnut | Good | Spring (late) to summer | Avoid if possible as regrowth is weak and heartwood is quick to decay |
| Lime | Good | Spring (late) to summer | |
| Magnolia | Fair | Summer (mid) | Reduces bleeding and allows time for healing to begin |
| Maples (inc Sycamore) | Fair | Summer or winter (mid) | Prone to bleeding (Field maple less susceptible) |
| Mulberry | Good | Winter (mid) | |
| Oak | Good | Spring (late)to summer | |
| Plane | Good | Spring (late)to summer | |
| Poplar | Good | Winter (mid) | Prone to bleeding |
| Robinia | Good | Summer (mid to late) | Prone to bleeding |
| Rowan | Fair | Spring (late) to summer | |
| Walnut | Poor | Summer or winter (mid) | Prone to bleeding |
| Whitebeam | Poor | Spring (late) to summer | |
| Willow | Good | Spring (late) to summer | |
| Evergreen trees | |||
| Cedars | Poor | Winter (mid to late) | Avoid any pruning if possible. Shoots will not grow from old wood – therefore prune lightly. |
| Cypresses | Poor | Spring (late) to summer (early) | Shoots will not grow from old wood – therefore prune lightly |
| Firs | Poor | Summer (late) or winter (late) | Avoid any pruning if possible. Shoots will not grow from old wood – therefore prune lightly |
| Hemlock | Fair | Summer (late) or winter (late) | |
| Holly | Fair | Winter (mid to late) | |
| Holm oak | Poor | Winter (mid to late) | |
| Pines | Poor | Spring (late) | Avoid any pruning if possible as buds only at shoot tips. Newest growth can be removed during the spring |
| Spruce | Poor | Summer (late) or winter (late) | Shoots will not grow from old wood – therefore prune lightly |
| Western red cedar | Fair | Winter (mid to late) | |
| Yew | Fair | Summer (late) or winter (late) | |
