When Should I Prune my Willow Tree?

Late winter to early spring

Expert insight into the best time for willow tree pruning; why you should prune a willow tree, and how to identify common diseases.

There are around 400 species of willow tree, known in Latin as Salix meaning ‘sallow’. When mature, willow trees grow to around 10 metres tall and have long lifespans up to 300 years. Most willows enjoy a wet, boggy environment so will usually be found growing close to rivers, streams and lakes.

Mostly when anyone mentions a willow tree, you will automatically think of the ‘weeping willow’, or Salix babylonica. The long, trailing branches that are characteristic to this particular tree sweep gracefully in the breeze, providing much welcome shade for park-goers and wildlife alike.

Whilst there are many UK native willow tree species prevalent throughout the country, including the bay willow, the crack willow, the goat willow, the osier willow, the grey willow and the white willow, we are specifically going to study in this post the pruning of the weeping willow, as it is one of the most popularly adopted in parks and gardens. Look out for future posts covering the other willow tree species or you can ask us to write a guide for your particular tree.

Why prune a weeping willow tree?

The weeping willow is a fast growing tree that benefits from good pruning and shaping in its formative years. Correct pruning of willow trees whilst they are still young and therefore easier to prune will usually make things much easier as time goes on. Develop a good structure now, and it should remain strong and healthy into old age.

When you prune a willow tree sapling, your aim is to develop a strong central leader. This will later become the tree’s trunk. You are also looking to remove any branches growing too closely together to allow more air and light to penetrate, which is essential to maintain the health of the tree as well as for aesthetic shaping. You’ll also want to test branches for strength and remove any that appear weak as these will usually break as the tree matures.

The aim of pruning a mature willow tree is really just to eliminate broken branches and those that are rubbing against each other and causing weakness. You’ll want to remove lower branches so that there is enough space to enjoy the shade under the tree during the warmer months spent outside in the company of your willow. It is also important to shorten the trailing branches if the tree is overhanging a public footway or land that needs to be maintained.

Additionally, because the willow tree grows rapidly, it can be prone to wind breakage. Spacing the branches will promote good air circulation which will reduce the risk of breakage. It is also important to remove suckers that come up from the ground should be cut off at ground level or below as they will drain energy from the tree.

When is the best time to carry out weeping willow tree pruning?

The weeping willow tree should only be pruned during late winter to early spring when the tree is in its dormant period. This is because willow trees, like most trees, bleed sap if they are pruned during their active growth period. When the sap is exposed it attracts bugs, which bring with them fungal spores and bacteria, which can lead to disease.

Of course if there are dead or broken branches posing a hazard, these can be carefully removed at any time.

Branch trimming to create space under the tree’s canopy can be done at any time of the year although it is usually most necessary in spring, summer and autumn. Suckers can be removed at any time and this should be done as soon as they appear.

Remember that you want to keep the lower part of the tree free from branches, so if you keep a close eye on your willow tree, you may be able to catch new growth early on and it will be as simple as rubbing it off with your fingers.

What to look for during willow tree pruning

Willow trees are prone to a number of diseases and pests. The gypsy moth caterpillar, the willow leaf beetle and the bagworm are all known pests, all of which will result in loss of leaves.

Crown gall is a particularly serious disease affecting willow trees which causes dieback and stunting. Also look out for green spores on the underside of leaves which denotes willow scab, and dark brown spots on the leaves which is black canker. Red or yellow patches on the trunk could be sunscald, which the tree will heal itself from in time, although it can be prevented in the first place by painting with diluted white paint.

If you spot peeling bark, this will usually be a sign of borer insects which have been tunnelling through the inner layer of the bark. Clipping out all affected branches is the best course of action in such cases.

Tree Preservation Orders

Never proceed with any tree work without first checking whether there is a Tree Preservation Order (TPO) in place. If there is one, then permission must be obtained for the works which can take up to eight weeks to come through. Also, if the tree is located in a conservation area, permission must be obtained before commencing works of any nature.

The importance of Willow tree pruning expertise

Due to the expansive height and width of the willow tree, and its common location nearby bodies of water, it is usually a wise move to call in professional assistance when pruning a willow tree. They will have the knowhow and skill to prune the tree in just the right way so that it maintains a strong structure, looks attractive and stays healthy.

The fact that the willow tree is prone to numerous diseases and pests is another reason why a qualified arborist really should tend to the tree on a regular basis. Spotting signs of disease early on will give the tree the best possible chance of survival.

If you have a willow tree on your land that needs pruning, why not contact Tree Works? As fully qualified and comprehensively experienced tree surgeons, we are able to offer specialist knowledge and skill in all aspects of willow tree pruning. For a free, no-obligation quotation, give us a call on 07781 416 354 or get in touch here.