Winter is the ideal dream time for cold-climate gardeners, but it’s also a perfect time to review good gardening practices and increase your gardening knowledge. For this Winter Review we’ll examine winter pruning.
You can take advantage of sunny late-winter days by heading outside to complete some winter pruning. Shrubs are dormant during winter, which makes it the perfect time for pruning damaged, dead, or diseased branches.
I don’t suggest you prune all shrubs at this time. Those that flower on last season’s growth – think lilac, forsythia, pieris, mountain laurel, rhododendron – and flower in early spring are best pruned shortly after they finish blooming. If you prune these during late winter you will remove much or all of the upcoming blooms.
You should wait until early spring to prune shrubs that bloom on new growth. These include butterfly bushes, cotoneaster, and red- and yellow-twig dogwood. And if you are looking to prune hydrangea, you first need to know what type of hydrangea you have, then you should seek the advice of a knowledgeable professional rather than risk losing upcoming hydrangea blooms.
At this time of year, when winter still has a good hold on our weather but we are beginning to get intermittent sunny and somewhat warmer days, look to prune damaged, diseased or dead branches. If heavy snow has split or broken a branch, it doesn’t matter when the shrub or tree blooms. The damage limb must be removed.
Branches scarred from rubbing against another object – specifically crossed-branches – are easily identified now while branches are bare. Crossed branches lead to chaffing that opens the shrub to insect or disease. Crossed branches must be pruned to maintain the health of the shrub.
Notice the scarring on the larger branch in the photo to the left.
While not yet causing damage, they will rub against each other when winds blow. Any jagged stem ends can also be pruned at this time, as can unwanted suckers – thin new growth that has grown from the base but detracts from the shrub’s form or looks like it’s growth pattern will cause it to rub against a more mature branch.
It’s also important to remove any suckers growing from below the base union – usually a fatter section at the base of the plant where a graft was added to rootstock – or from beneath the soil of a grafted shrub. These are growing from the rootstock rather than the grafted, and more desirable, section of the shrub.
The exception to removing suckers shrubs and trees that have not been grafted to a rootstock, is when new suckers are needed to replace old or damaged branches. If you plan to keep the shrub, select suckers can be left to grow and become mature replacement branches.
Pruning is a necessary part of maintaining shrub and tree health, but it can also be a very confusing part of garden maintenance. When in doubt, ask advice from trusted, well-trained local garden center staff. Or, hone your pruning knowledge by reading. I often reference Pruning & Training by Christopher Bricknell and David Joyce. State extension offices often post great pruning advice online, as well.