Prunning Ornamental Trees and Shrubs

To begin pruning most any tree or shrub you always begin by removing any dead, diseased or damaged branches.  How we next proceed depends on what we are trying to achieve.  A typical reason for getting us out in the yard to prune is that a plant or plants have out grown their space and are intruding on a walkway, driveway, house, or other plants.  All too often the answer to this problem is to get out the shears and cut the outside of the plant back to a ball, box or some semi vase shape.  The shearing process should be reserved for a planned formal accent to a garden and we will discuss that process later.  To cut a plant back in size and retain its natural form and beauty you will need the proper tools:  bypass or anvil pruners, loppers and a hand saw. 

If the plant we need to prune back has overgrown its space it is probably also too dense and will need to be thinned.  The obvious beginning is to cut back any branch growing out where you do not want it.  The key for all cuts is to not cut in the middle of a branch.  Always remove a branch from its base or crotch. (the spot where it attaches to another branch).  This is the most important rule in pruning.  The result of cutting a branch too far from its origin is multiple branches sprouting from the cut.  This is called “witches broom growth” expamples of this can be seen in many communities where power companies cut back trees from power lines.  This practice dramatically changes the form of the plant, puts excess stress on the plant and .inhibits flowering and fruiting; Here is a list of characteristics to look for to decide what branches to be pruned:

• Damaged or diseased wood
• Water sprouts or sucker growth.
• Branches intruding on another space ( walks, buildings, driveways ).
• Crossing branches

• Branches growing closely parallel to each other. (pick one to keep and remove the other or others)

By selectively pruning we are diverting the plants growth energy to stimulating new growth, fruiting and flowering.  Typically we want to encourage the plant to take its natural form and enhance its beauty and health by removing the dead, diseased or damaged wood as well as water sprouts.  If the plant becomes too dense then many of the interior branches will begin to die off.  This can be avoided through thinning.  This is when we look for crossing and closely parallel branches to remove.  In some cases we may even want to selectively remove canes from the base of the plant to open it up.  I will do this a lot with Viburnum, Spirea, and Forsythia as all these can become very dense and I prefer a more open form.

Shearing is used to create a formal look in the garden and is done without regard for nodes but simply to shape a plant in a consistent form such as a hedge.  However it is important to occasionally take our bypass pruners and thin the plant out by removing growth from the center of the plant to let sun inside and allow new growth to come from the center of the plant.  This should be done every year to avoid the need for drastic pruning that can be unsightly until the plant recovers.  When shearing a hedge for the first time it is a good idea to run a string line to assure a consistent height and width.  The plant or hedge should be pruned to a slightly pyramidal shape to keep the base of the plant from becoming shaded.

 Plant choice for shearing is an important consideration.  Some plants do not lend themselves to this practice.  Look for plants with small leaves or needles such as: Boxwood, Privit and Yew.