Spring Prune Up

Early spring is a great time to get the gardening season under way. March is the ideal time to prune woody ornamentals. The branches are still bare, revealing the structure of the plant and making any necessary shaping a snap. Additionally, insects and diseases that might attack an open wound are not active, making it easier for the plant to recover.

There are many reasons to prune a woody ornamental, to include maintenance, shaping, recovering an overgrown plant, and encouraging flowering. To begin, first, choose the proper tool for the job. Several tools can be used for pruning: bypass pruners, anvil pruners, loppers, and small tree saws. The particular tool should be determined by the type and size of wood to be cut.

Bypass pruners have two curved blades; a thin sharpened blade and a thicker unsharpened one. When cutting, they pass one another similar to the way scissors operate. These pruners are best used when trimming tender, living branches. Anvil pruners, have only one sharpened blade that closes down on a hard edge or anvil, similar to a knife and chopping block action. These pruners are best used on hard, dead wood since they tend to crush the more tender branches. Both bypass and anvil pruners are good for branches up to an inch in diameter.

Loppers are available with both bypass and anvil type blades. The advantage to these pruners is their longer handles. The extra length gives the operator the ability to reach further and get greater leverage. They are ideal for trimming hard to reach branches, those with thorns, and any branch from one to two inches in diameter.

Tree saws are used when dealing with branches larger than two inches in diameter.

Do not prune spring flowering shrubs such as lilac, dogwood, forsythias, weigela, or viburnum in March because it will compromise the flowering for this season. Wait to prune these plants until after they have flowered.

Deciduous shrubs are pruned using three methods: heading back, thinning, and rejuvenation. Heading back is defined as cutting off a portion of a stem or branch. This causes the plant to focus growth beneath the cut. The shape of the plant is determined by cutting either inward or outward growing buds. Cutting just above a node or another branch will result in a dense, compact shrub with a natural form

The next method is thinning or renewal pruning. In this case, approximately one-third of the stems are removed each year. Cuts are made low in the plant, as close to the ground as practical, starting by cutting out the oldest or largest stems from the center. In addition, cut out branches that are pointing inward, cutting again directly above a larger branch or bud. This allows more air circulation and better sunlight penetration and resulting in a more vigorous plant with better flowering. When pruned correctly, the shrub will initially look quite thin, but will fill out as the season progresses.

The last method is rejuvenation pruning. Not all shrubs will tolerate this method, however dogwood, honeysuckle, some hydrangea lilac, potentilla, spirea, and weigela can. In fact, most potentilla will perform best if they are rejuvenated every year, responding with better blooms and a neater appearance. Cut all the stems down to six to twelve inches of the ground. New growth will sprout from low growing buds.

Carol Shirk

Certified Master Gardener