P. Allen: Ready-Set-Prune

Plants You Should and Shouldn’t Prune in Late Winter

by P. Allen Smith

The first thing that everyone should know about pruning is that much like a bad haircut, a botched pruning job will grow out eventually. It’s unlikely that a person will kill a plant with poor pruning. It may look really bad for a while, but it won’t die.

The chances of getting the job done right are improved if you use good, sharp tools, make a clean cut and consider the growth habit of the plant. And you can’t go wrong by just removing dead wood, crisscrossing branches and by limiting the removal to one-third of the plant’s size.

The most obvious reasons to prune are to reduce the size of a plant, maintain a plant’s shape or improve its appearance. Pruning to remove dead and diseased wood or thin out the center branches will also help keep a plant healthy. For instances, shrub roses or hydrangeas that have grown too dense benefit from the removal of interior branches to open up air circulation; good air circulation helps keep diseases in check.

Pruning in late winter when many shrubs and trees are dormant invigorates the plants for abundant growth in spring; the wounds are exposed for a limited amount of time before the growing cycle begins; and finally, it’s just easier to see what needs to be pruned after the leaves have dropped.

In this part of the country, late winter is February. The garden is still dormant but the spring thaw will begin within four to six weeks. The job should be handled before new spring growth begins but after the threat of severe cold has passed.

What to Prune in Late Winter

Here is a short list of plants that appreciate a good trim in late winter.

•  Summer flowering trees – Ornamental trees that bloom in summer such as crape myrtles, vitex, smoke tree and rose of Sharon

•  Hydrangea paniculata and H. arborescens – Unlike their cousin H. macrophylla, these two hydrangeas bloom on new wood, so cut them back hard to promote growth and flowers.  H. paniculata can be cut back to two buds above the base of the flower stem. Prune H. arborescens back to varying heights of one to three feet from the ground.

•  Fruit trees – Fruit trees flower on growth from the previous season, but pruning should be done when the tree is dormant, so there will be some flower and fruit loss.  The good news is that pruning promotes vigorous growth and larger, better tasting fruits.  Each type of fruit tree has some special requirements so do some research before you begin cutting.

•  Roses – Hybrid tea, old-fashioned and climbing roses should be pruned right before the leaf buds break or if you live in a northern region, pruning should be done when you remove winter protection.

What NOT to Prune in Late Winter

Not all plants should be cut back in winter.  This is a list of plants that prefer to have their haircuts in late spring or summer.

•  Spring flowering shrubs – Forsythia, quince, azaleas, bridal wreath spirea and other shrubs that bloom in spring should be pruned immediately after they flower.

•  Spring flowering trees – Lilacs, ornamental fruit trees and Eastern redbuds, for example, should be pruned right after the trees have finished flowering.

•  Hydrangea macrophylla – Old-fashioned, pompon hydrangeas set bloom buds on the previous year’s growth.  It’s safe to remove faded flowers and dead branches.

•  Once-blooming roses – Old-fashioned roses that only flower once each growing season, such as Damasks and moss roses bloom on old wood and should be pruned in the summer after they have flowered.

•  Gardenias – These should be pruned immediately after they bloom.

•  Bleeding trees – Maples, birches, dogwoods, walnuts and elms produce copious amounts of sap when they are pruned in late winter.  Pruning won’t hurt the trees, but it will be less messy if you wait until summer.

Essential Tools

The best results come from using sharp, clean tools that are suited for the task. Here is a list of pruning essentials.

A sharp pocket knife is great for making small cuts as needed.

Hedge shears are designed to cut small twigs or shrubs, but not anything much larger than the size of a pencil. They are a must for broadleaf evergreens such as boxwoods, hollies and yews.

Bypass pruners are suited good for cuts about the size a pencil and can be used for perennials and shrubs with thin stems like roses or azaleas.

Loppers are a tool for making big bites when you need to get some leverage. They are best for using on dead wood because they tend to crush rather than cut. This crushing action can damage living cells in a branch, which could cause a longer healing time for the tree or shrub.

Saws are also ideal for large branches and can be used for cutting living wood. The more teeth on the saw the finer the cut and the easier the healing process will be on the plant.

Pole saws and pole pruners are handy for reaching into large shrubs or for working overhead.

Good to Know:  When to Call in a Professional

If you can’t reach a limb from the ground with a pole pruner, it’s time to call a pro.  This also applies if the limbs are heavier than you can manage or if the tree is near power lines.