Shrub pruning is best done in late winter or early spring, although light pruning can really be done any time of the year. Severe pruning in late summer should be avoided, since new growth may not have time to mature before cold weather occurs.
There are five basic ways to prune shrubs:
- Thinning - This technique cuts a branch off at its point of origin from either a parent stem, side branch, junction or at ground level, resulting in a more open shrub without stimulating excessive new growth. Thin out the oldest and tallest stems first, to allow brisk side branch development.
- Heading Back - Removes the terminal portion of a woody branch by cutting it back to a healthy bud or branch. Heading back stimulates growth below the cut thus making the plant denser. Cutting to inward or outward growing buds can influence the shape of the shrub. The top bud should be situated on the side of the branch that faces the direction of desired new growth.
- Pinching – Removes the terminal portion of a juicy, green shoot before it becomes woody and firm. Pinching can greatly reduce the need for more dramatic pruning later on. When you see a shoot becoming excessively long simply pinch or cut the shoot to reduce its length and to promote side branching. Long, vigorous shoots should be cut back into the canopy instead of cut at the outer limits of the existing foliage.
- Renewal or Rejuvenation Pruning - Removes older shrub branches by pruning them close to the ground, leaving only the younger, more vigorous branches. Alternatively, renewal pruning can entail cutting all the branches back to a set height at the start of each growing season.
- Shearing – This method should only be used when creating formal hedges. Shearing destroys the natural shape of the shrub, causing more growth on the exterior of the plant that excludes light from entering the center. Foliage on the interior of the plant therefore dies and the natural renewal growth from within the plant in prevented.
