Hard pruning works well on mature shrubs like viburnum and mahonia bushes. Pruning very low to the ground, (leaving approximately 15cm to 30cm of the pruned stems above ground), will encourage the plant to grow vigorously in the spring, producing lots of new stems. It may seem like a drastic thing to do, but the plants really respond well.
Now is a good time of the year to hard prune many overgrown shrubs, whilst the plant is dormant.
However, shrubs that flower early in the year, such as forsythia, are better pruned immediately after flowering in the spring. Hard pruning now will remove next year’s flower buds and reduce its flowering.
Before you start, ensure you’ve got the correct pruning tools with you and that they all have clean, sharp blades.
The tools you’re likely to need are a pruning saw, a pair of loppers and secateurs.
If the shrub you’re pruning is an overgrown rose, you’ll also need a thick pair of gauntlet style gloves.
Firstly, take a good look at the shrub to identify the oldest branches which are usually darker brown and thicker than the others.
Other things to look for are the three D’s. These are dead, diseased, and dying. Finally, look for branches that are crossing with other branches as they are likely to rub their protective layer off and allow potential diseases to take hold.
If the shrub hasn’t been pruned for several years, it’s best to remove about a third of the oldest stems each year for the next three years. This way you’ll still get flowers the following year.
Then, give the shrubs a balanced nutrient feed and watering immediately after pruning.