Pruning and cold weather protection

October 4, 2023

Well…I hate to state the obvious, but this year we had a rubbish summer here in the UK!  And we seem to have arrived at autumn and soon winter all too quickly.  

Every year at around this time I get asked by clients if it’s okay to prune in cold weather and what essential tasks need to be done, plus a few people are scared of pruning and doing the wrong thing. I hope this blog will help you understand the benefits of pruning, what to prune when, and how to prepare your garden ready for spring.                            

What is pruning?

Pruning is carried out for a variety of reasons - to promote bigger harvests, get newly-planted trees and shrubs off to a good start, thin crowded stems, train cordons, fans, and espaliers, encourage flowering, shape plants, remove diseased wood and promote resilience.    

Generally, we prune in the winter for three different reasons:

  • For higher productivity and resilience, especially for plants that bear edible fruit, such as grapevines, raspberries, currants, and gooseberries.
  • To reshape the plant. This applies to ornamental vines and shrubs that have grown too large or look lopsided and need a quick tidy-up.
  • To prevent overgrowth - think about what would happen if you let super-grower perennials such as wisteria go unchecked. They would take over any structure that had the bad luck of standing in their way.

When is a good time to start pruning?

Ensure that the cold frosty weather has passed for the season before pruning because early pruning can prevent the new season's growth from occurring, as pruning stimulates new growth.

While plants are dormant, it's also a good time to carry out renovation pruning, to revive plants that can become large and unproductive, such as viburnum and mahonia. Pruning in winter can also help control or prevent the spread of disease.

How cold is too cold to prune?

Large cuts and cuts on young trees are potentially the most hazardous. If below-zero temperatures are predicted, all pruning should stop at least 5 days before the cold weather is expected.

Plan to prune!

It’s very important to carefully plan your pruning as the cold affects plants and trees in different ways. Trees for example are more sensitive to the cold and young trees more than large trees. So plan to prune your healthiest, plants and trees at the time of year when cold spells are most unlikely to occur.

The pruning jobs that can be done in winter/spring

As a general rule, always trim/prune and tidy when a shrub has finished flowering.  Here is a list of when to prune our favourite/most popular plants:

  • Hydrangeas - prune in March when the new shoots are visible. If you cut the old flower heads off too early your plant won’t flower. You can use this opportunity to reduce the size too.
  • Fuchsias - always leave until the spring when new green shoots are visible, then prune the woody stems off. The plant then produces better flowers!
  • Roses -  always prune in December - don’t be scared! There is a saying `let your enemies prune your roses’. For shrub, bush, and patio roses, always take down to about 6 inches to a foot depending on the original size. For climbers, cut everything off to the main stem. Check around the base of your rose too and remove dead wood.
  • Lavenders - these have really suffered in the recent weather conditions. To avoid a lavender getting too big, prune them hard to about 6 inches, they should grow back strong and flower well.
  • Perennials - snip off any brown stems you find in spring, it won’t do any harm.
  • Cordyline - to protect from a hard winter, just tie the leaves up, you can also wrap them in fleece and mulch around the base to protect the roots.

Three ways to protect your plants in cold weather  

Many plants can survive a brief frost, but very few can survive a hard freeze. Frost damage occurs when the liquid in the plants’ tissue freezes and bursts due to the cold temperatures.

Water the plants during the day

Water your garden soil thoroughly during the day before evening frost is predicted. Damp soil can hold four times more heat than dry soil. It will also conduct heat as the soil releases moisture and warm the air near ground level. Watering your garden when temperatures are still above freezing will help hold in some thermal heat when the temperatures dip overnight.

Cover plants with old blankets and sheets or a garden frost blanket

Old blankets and sheets are a great way to protect plants from frost. The blanket will help insulate tender plants and keep them alive during a frosty night.

Use stakes or hoops to hold the material up and away from the foliage and drape the blanket over the plants until it touches the ground. Secure the edges with boards, stones, or bricks to hold them in place to prevent cold air from seeping in.

Add heat

If the predicted overnight frost is unusually cold, extra heat may help keep your plants from freezing. In addition to covering frost-tender plants, you can add heat beneath the cover.

Fill milk jugs and containers with hot water and place them under the protective covering to serve as a source of extra heat around the plants.  Use a string of older, non-LED lights to help keep plants warmer. String the lights along the arch supports beneath the coverings. Keep the lights from touching your plants and fabric.                                                

And finally…loppers, pruning saws and secateurs?

Top tip: If using secateurs always cut at a slant (45 degrees to be technical), this will allow rainwater to run off and prevent damaged stems.

Whether it's a pair of long-handled loppers, pruning saw or secateurs, using the right tool is essential for the task at hand.  Please check our next blog where we uncover the different types of tools to use for pruning and beyond!

How CJ Garden Services can help with your garden pruning

At CJ Garden Services we work with clients who need assistance with winter pruning and end-of-season garden tidy up plus offer general help and advice to protect their gardens from the cold.

To find out more about how we can help you, please get in touch with us today.