What to prune in December and January – and what to leave alone

Our gardens can seem inhospitable places during the depths of winter; light levels are at their lowest point, and there’s often that grey, drizzly weather that makes it so easy to stay indoors. However, during the darker months of December and January there are golden moments of sunshine, and those dry, cold conditions can be invigorating and spur you on to sharpen your secateurs and get out there.

Believe it or not, there are a few plants that respond well to being pruned at this time of year, which puts you on the front foot, horticulturally speaking, for the busy spring ahead. The shrubs and trees that need pruning during December and January are incredibly hardy and we’re looking to work on these plants during their dormant state to minimise the amount of shock that we inflict with our pruning.

The joy of pruning roses, apples, soft fruit and wisteria at this time of year is that we get to analyse the plant’s outline and can create symmetry and balance, but also identify any dead, dying or diseased wood.

Sharp secateurs, loppers and saws are essential when it comes to any pruning. When spending an afternoon in the garden carrying out this surgery, it’s worth making sure that your tools are sharp, as it is not only better for the recovery of the plant but much safer for you too.

A blunt or poorly maintained saw or pair of secateurs will require a much greater force to make the cut, and by inflicting that greater force, you might accidentally slip and prune yourself during the process. Secateur and lopper sharpening tools are available online, and if you’re carrying out an extensive amount of pruning, then it might be worth investing in a new blade for your saw to get the best results.

Wisteria

Wisteria pruning can be a daunting and baffling process, but the wintertime is a key moment to train and encourage your wisteria to flower later in the year. For the first few years, you want to train as much growth as possible to create a framework, tying in new shoots as they develop. Providing coverage of your structure or wall with more horizontal growth will in turn encourage more side shoots and flowers.

Although I want to focus on winter pruning, I’ll briefly touch on summer pruning, which involves managing a lot of the whip-like growths, by either tying them in or trimming them back. During July we’ll be looking at reducing a lot of the growth to about six or seven buds from its origin that year, to ripen the wood and encourage side shooting.

During the dormant period of your wisteria, which will be from December through to February, reduce the previous year’s growth down to about two or three buds. By reducing these shoots, we’re encouraging more branched growth and larger flowers for greater impact.

Where you see wisteria grown up a tree, it’s not always practical to carry out regular pruning, but by not managing the wisteria, it simply means that lots of flowers will be produced, and they will be smaller. Regular pruning often controls wisteria in a way that’s more suitable for domestic gardens, and by encouraging more light into the canopy, and more horizontal growth, we also encourage a better flowering performance.

While you’re carrying out your winter maintenance, check for any root suckers that may be erupting from the base of the wisteria.

Remove these just below the soil because, left unchecked, they become dominant and will compromise your wisteria’s flowering performance. Attributes such as white-flowering wisteria will often have a purple-flowered rootstock, and if left it will outcompete and replace the white-flowered wisteria over time.

Roses

When it comes to roses, we want to prune and tie them down in such a way that they hug the trellis, the shed or the arbour that we want them to cover, as well as remove a percentage of older stems each year to rejuvenate the plant.

If we were to leave our roses unpruned, they would become a bird’s nest of thorny growth and would look less attractive, with fewer flowers.

With climbing and rambling roses, we’re looking specifically to reduce side shoots and tie in new growth in a pleasing shape that is flush with the structure that we are tying them to.

Prune late raspberries

Late-fruiting raspberries don’t generally grow as tall as the earlier fruiting types and are much simpler to manage and prune. Simply cut the old, fruited canes from last year down to ground level. I like to leave enough of the cane above the surface to be able to see where my raspberries are, but this is not essential.

Prune gooseberries

Some gooseberry bushes can have very long growth that almost becomes pendulous in its habit; these long growths should be reduced to a more upward-facing bud. The degree to which you reduce the shoot will depend on the vigour and variety of your plant.

Remove any low-lying branches close to the ground whose fruit will be compromised by contact with the soil.

Side shoots on your gooseberry, often fruiting spurs, will carry your fruit this summer. Reduce these side shoots to around three buds to promote fewer but larger gooseberries.

Prune blackcurrants

The most productive blackcurrant stems are often two or three years old; make sure that you have a number of these most productive stems left on the plant after pruning, to produce fruit.

Remove some of the oldest stems each year at the base, to make way for new stems and shoots to reinvigorate the plant.

Remove any low-lying branches and congested areas within the centre to allow for maximum air movement and reduce the potential for disease.

Springtime is ideal to mulch your fruit; avoid piling up the compost in the centre of the plant, which will lead to rot and disease.

What not to prune at this time of year

Before all this pruning-related adrenaline goes to your head, and you feel like inflicting some sort of chainsaw massacre in your garden, there are several shrubs and trees that will not respond well to being pruned at this time of year.

Any tender plants, whether that be deciduous types or tender evergreens like cistus, convolvulus and lavender, will probably die back to the point of no return if they are interfered with at this time of year.

Although this is a good time to prune apples and pears, avoid pruning cherries and plums during the winter as they will be more susceptible to silver leaf, a disease which is more prevalent during the winter.