When and why to prune

Seasonal pruning, maintenance pruning,  hedge trimming, fruit tree pruning, rose pruning, why to prune, when to prune, right time to prune, pruning and climate change,  confused seasons pruning, gardener Bourne End, Marlow, Taplow, Wooburn Green gardener

When and why to prune is a vast subject, and so this article aims to describe the basic principles. There are several reasons to prune, which have differing degrees of importance to the homeowner and gardener alike.

The main reasons for pruning

Pruning is carried out for these reasons.

• Maintaining the health of the plant
• Manage the size of the plant
• To get the best from a plant, for its beauty, or for its yield
• Necessary horticultural pruning, or aesthetic pruning
• Safety pruning, removing material that can endanger people

The very worst thing that can be done is not to prune. Many clients refer to letting the plant grow bigger for privacy, but that often produces unruly open plants that offer very little privacy.

Regular management removes dead, damaged and diseased wood, maintains shape and character, airflow and overall size. And if your plant exists primarily to provide something to your garden, i.e., scent, colour or crop, those values can be enhanced.

Sometimes the horticultural requirement is more important, and sometimes the aesthetics and practicality control what needs to be done. Ultimately, the homeowner – and bill payer – decides whether the size and shape is more important than the health of a plant.

When is the right time to prune

Late winter and early spring are often the best times to prune. There are obviously some exceptions, including plants that can be damaged by cold weather, or that flower early in the year.  Winter is the best option as many plants are dormant. The sap is not rising, and plants will not bleed from the wounds. This allows time for wounds to heal before sap starts rising again as plants come into bud.

Winter pruning without leaves makes structural pruning much easier, leaving maintenance pruning as a lighter task when plants are in full leaf.

Climate change has caused some confusion in the seasons, in that what used to be a fairly know timeframe could now have a much larger – or narrower – window. So “late winter” and “early spring” may not be the same from one year to the next. According to the Met Office,  winter doesn’t start until December 21st, making late winter February 21st through March 21st. Casting our minds back over the last few years, other than late frosts, March has been warm. This uncertainty, or vagueness leads us to conclude that it may be better to prune when we know it is coldest, and plants are most dormant, into January and before the end of February – a much shorter window.

Some plants, such as grape and walnut, are particularly vulnerable to bleeding if pruned in mid- to late winter or early spring, as the rising sap spills out from the pruning cut.

Pruning exceptions

Being aware of these subtleties is what makes a gardener. Knowing to prune before the buds start swelling, but not so early in winter that the plant could suffer winter injury.

There are a large number of plants that flower early in the year, which if pruned early would deprive them of their primary purpose. But that may be a worthwhile sacrifice for a year if the the plant needs urgent or radical attention.

A couple of rules of thumb for pruning. If the plant flowers after midsummer, prune in winter. If it flowers before midsummer, prune after flowering. And as Christopher Lloyd said, it’s OK to do it when you think of it, have time to do it and have the tools to hand, than not do it at all.

Objectives of pruning?

• Cut out all dead, damaged and diseased wood.
• Thin out crowded and dense limbs.
• Trim watersprouts from limbs on trees.
• Cut out all crossing or rubbing branches.
• Remove weak wood and thin growth.
• Cut back at least 6″ to healthy wood on any dead wood.
• Remove suckers.

The plant and its condition dictates the pruning requirements. Most deciduous shrubs will benefit from thinning or heading, or both. Removing old growth at the base of the shrub, and new weak or thin stems will give room for air circulation and light. If a plant requires significant reduction, do it in phases allowing growth to resume between. That way we don’t shock a plant, or reduced it to a pile of sticks. It then has chance to recover and regrow from low down. This is  way a plant to scale back safely over a period of one to three years.