Deciduous shrubs are pruned to keep them healthy, tidy, attractive and to encourage more flower growth. Shrubs are very forgiving and will thrive if a few simple pruning rules are followed.
Always cut back to the ground or to another branch. Stubs that are left are unattractive and hard for the plant to heal meaning that insects and diseases will have easy access to the interior of the branch.
Do not worry about using a pruning paint on cuts. Research has found that it is not effective in sealing the wounds.
Do not remove more than a quarter of the shrub at one time. Removing more will cause the plant to produce a massive amount of watersprouts, thin long stocks, that will need to be removed.
Start pruning by removing all dead and diseased branches. Diseased branches should be double bagged and placed in the garbage or burnt immediately to stop the infection from spreading.
Once the dead growth is removed, look at the plant’s shape. If the shrub has not been pruned for a number of years the plant’s center will be dense with branches and leaves only on the uppermost branches. Removing a number of mature branches from the center of the shrub will open it up to sunlight and air, which encourages new growth. When deciding which branches to remove, look for ones that cross other branches. Cutting these out will prevent branches rubbing and damaging bark.
Depending on the location of the shrub, it might also be important to lessen the height or width of the plant. Plants should not block driving visibility, grow over windows or block paths.
When pruning to reduce a plant’s size, cut back to another branch at the desired height.
Lastly, shape the plant.
Always keep an eye on the growing brush pile and stop removing live branches when a quarter of the branches have been removed. More can be removed in following years.
Shrubs are very forgiving plants and rarely die from over pruning but removing too may branches at one time results in numerous watersprouts, long and straight sticks. Watersprouts rarely harden off in the fall and are dead by spring. Cutting out to much of the shrub at one time results in wasted plant growth and more pruning.
Deciduous shrubs that bloom after the middle of June, bloom on the current year’s wood and should be pruned when they are dormant. Examples being Spirea, Mock orange and Potentilla. Once the leaves have fallen it is easier to see limbs that are injured, diseased or crossed and rubbing. Exceptions on dormant pruning are early blooming shrubs, ones that bloom on last year’s wood such as; Lilacs, Double Flowering Plums, Nanking Cherries and Forsythia. These plants should be pruned shortly after they bloom as they start to develop next year’s flower buds shortly after flowering. Pruning when they are dormant will remove next season’s flowers.
Pruning a shrub is easy. Follow a few simple rules and the plant will respond with new growth, flowers and a pleasing shape.
Linda Tomlinson is a horticulturalist who has gardened in the area for over 30 years. She can be reached at email@example.com.