Pruning your shrubs and roses is important to keep your landscape beautiful. A well-pruned plant will be more resistant to disease, will have increased vigor, more flowers, and more luscious growth and color. A little pruning each year makes the job a lot easier and keeps your plants in tip-top shape. New gardeners may look upon pruning with fear of disfiguring or killing their plants with improper pruning techniques. However, if you use the proper tools and take care with each cut you make, your plants will thank you for your pruning efforts.
The number #1 rule of pruning is: don’t fight nature. When selecting flowering shrubs or trees, save yourself some work by carefully considering the ultimate size of the plant and where it will be located. Pruning should enhance the natural shape and performance of your shrub or tree, and not be used to correct mistakes made in plant selection or placement.
When should you prune?
In northern climates like Michigan, plants like shrubs and roses can be pruned almost anytime during the spring and early summer with some exceptions. However, avoid pruning any roses, flowering shrubs or trees in late summer or autumn because this can stimulate tender new growth, which is susceptible to damage by cold temperatures.
Spring flowering shrubs such as forsythia, purple sandcherry, flowering almond, lilac and azaleas bloom on the previous season’s growth, sometimes referred to as “old wood”. In other words, the flowers we see this April, May and June actually developed on the plant late last summer. For maximum flower production next year, prune spring flowering shrubs immediately after they bloom.
Summer and early-autumn flowering shrubs such as butterfly bush, rose of Sharon, spirea, hybrid and shrub roses and Peegee hydrangea bloom on the current season’s growth or “new wood,” which means flowers have developed since growth started that spring. These plants should be pruned just as growth starts in spring, preferably while still dormant.
Start with clean, sharp, good-quality tools appropriate for the job at hand. To prevent the possible spread of disease, clean your tools after pruning each plant with a solution of one part chlorine bleach to ten parts water.
Mature flowering shrubs benefit from pruning every two to three years. This helps maintain the plant’s health, vigor, and enhances its appearance.
Step 1: First, remove any dead or diseased wood. Next, select two to four of the oldest, largest stems, equally spaced around the shrub. When removing old stems, try to make the cut as close to the base of the stem as possible.
Step 2: You may need to prune some of the younger stems and suckers as well—start by removing any branches that are crossing or rubbing against each other, then prune those that look out of place or are crowding the center of the plant. Aim to leave a balanced variety of old and new, big and small stems.
Step 3: Now you are ready to give the plant its final shape. You will need to head back the stems that are too long to give the plant a nice shape. To do this, select the branches that need shortening and make the cut just above a bud that is facing in the direction you want the new growth to go – usually toward the outside of the plant. This keeps the center of the shrub open, which is important for good air circulation, and it gives a more natural look.
Special Instructions for Roses
Prune your rose bush only in early spring, never prune in fall or winter. Roses need a hard annual pruning to provide the most prolific floral display in the summer. Start by cleaning out dead wood and diseased, weak canes.
For Hybrid T and Grandiflora roses you want to thin out the oldest heaviest canes, leaving 6-8 strong, healthy canes to produce a full and shapely plant without overcrowding. Canes the diameter of your thumb are the most productive, canes that are larger in diameter should probably be removed. Once the heaviest canes are removed, the remaining canes should be pruned to a height of about 18 to 24”.
Floribundas, shrub, miniature and groundcover roses tend to have more branches by nature, so you may want to leave more canes on those types of roses. Roses of these types can be pruned to size and shape with hedge shears once the dead, diseased and a few of the oldest and heaviest canes are removed.
Shrubs and roses that are properly pruned and maintained create a vibrant landscape and provide beautiful and enjoyable surroundings that can be savored by homeowners and guests alike.