In general gardening terms, pruning is probably the most misunderstood gardening chore, and certainly, the chore that is most likely neglected. When we specifically look at pruning with regards to spirea, this misunderstanding and negligence can be magnified. Pruning has been described as a “combination of art and science.” Pruning a specific plant to look a specific way, involves art in creating a unique definition for a specific plant, and it involves science in understanding the physical growing habits of the plant to be pruned. The most important reason for pruning Shirobana Spirea is to improve the overall health of the plant. Many times, spireas that have not been pruned in a few years will develop dead or degenerative twigs. Removing the dead and dying limbs will minimize the possibility of diseases such as “dieback” and will also allow the plant to re-concentrate its energies. In many instances, spireas that have been neglected for a number of years will become infested with insects such as scale. Severely pruning such infested spireas will not only re-invigorate the plant, but will also reduce insect problems and minimize corrective treatments necessary to eliminate such problems. Another reason for pruning Shirobana Spirea is to re-define the plant’s definition within the landscape. Many times, a plant may outgrow its intended size in the landscape, and must be pruned to re-define its purpose. Pruning should always be associated with re-invigorating a plant by allowing it to focus its energies on producing more vigorous branches, foliage, and flowers. Specific plant objectives require specific pruning techniques. If a Shirobana Spirea is being trained as an hedge, it would need to be pruned differently than if it were being grown as a specimen form. Screenings and hedges of spirea would need to be pruned for their specific purpose within the landscape. It is also important to understand the specific growing characteristic of a certain plants when pruning that particular plant. When pruning established spireas where no labeling is present on a variety to identify it, you need to look at the general growth patterns of the plant to be pruned. These observations should give you a good idea of how the plant tends to grow, and also how you should prune the plant. Many times, gardeners inherit a wealth of shrubs in their gardens when they purchase a previously owned residence. Although these plants may have been lovingly cared for by the previous owner, it may be necessary to severely prune these plants to restore vigor or to create a different definition in the landscape for the new owner of the property. Severe pruning should be done just after the plant has finished blooming. In some instances where the required pruning would be drastic, the pruning may be done towards the end of summer even if the plant has not finished blooming. Severe pruning of spireas is generally thought to involve the removal of one third to one half of the existing plant. However, in some instances, this severe pruning could be even more drastic. In most cases, the plant should have no problem recovering from such a major pruning, and the pruned plant should quickly begin to grow with vigor. If severe, pruning is necessary, it must be realized that the plant will shift its focus in the short-run from setting flower buds to growing vigorously, and it is very likely that the Superstar Spirea will have few if any bloom buds during the season following the major pruning. During the second season following the severe pruning, the spirea should resume normal bud setting, and the plant should have healthier blooms because of the increased vigor in the plant. It is important to always use sharp tools when pruning plants. Knives, hand cutters, saws, and shears should be sharpened if necessary before pruning any plants. A sharp cut will heal quicker than a jagged cut, which will also minimize the likelihood of disease investing a cut during pruning. It is generally recommended to not use power equipment such as gas hedgers to prune spirea. Prune limbs flush to the feeder branches without leaving nubs. These leftover branches could eventually provide host for disease to enter your spireas. Many gardeners apply a pruning sealant or paint to all cut surfaces after pruning, but that practice is generally not necessary. Pruning large spireas may be minor or major. Its general purpose is to maintain or restore vigor to the plant. Large spireas that have been severely pruned have the advantage of a large root system that has excessive capacity, and its roots are capable of supplying all of its energies to a smaller number of branches and foliage. This enables the plant to increase its vigor, and become healthier. Pruning large Shirobana Spirea Shrubs that are well established will enable the plant to have continued vigor, and lead to many more years of supplying beauty to the landscape.
