Shaping Growth of
Shrubs and Trees
There are many reasons to prune and control shrub growth in landscape plantings, beds, and borders, including health, appearance, and size.
Pruning is Necessary and Useful
Among the many reasons to prune shrubs are controlling a shrub’s size and improving its shape. Your goal will influence the type and the timing of your pruning.
You may wish to promote flowering and fruiting, remove dead or diseased stems, or create a more open look. Some pruning, on the other hand, encourages a fuller, leafier appearance.
It seems strange that pruning a shrub can make it grow back thicker and bushier. The way plants grow make both possible.
Every branch has a growth bud at its tip, along with lateral buds lying along its stem. (Run your finger over a bare branch in the winter, and you’ll discover this immediately.)
Let’s learn two terms: The bud at the tip of every branch is called the “dominant bud.” It has what plant experts call “apical dominance.”
Apical dominance is the power that stops other growth buds on the stem from sprouting. The dominant one on the tip hogs most of the plant’s nutrients so it can grow.
As long as a branch remains intact the dominant bud grows steadily and the branch keeps getting longer.
But if you trim off that dominant bud by pruning the branch, latent buds below the cut start to sprout and grow. The branch doesn’t keep getting longer, instead it gets fuller.
Lightly pruning all of a shrub’s branches encourage a flush of new overall growth. Its outer canopy grows more dense and looks better in the landscape.
This type of pruning cut, made at a slight angle just above a lateral bud, are known as “heading cuts.”
Repeat heading over the years may make some shrubs unhealthy. The dense new growth on the plant’s exterior shades out the shrub’s interior, and it dies.
In such cases, so-called “thinning cuts” open up the interior to more sunlight. The shrub’s interior begins to grow again and it becomes less leggy. It’s health and life is also improved.
Thinning cuts are similar to heading cuts but are made by reaching deep into the plant’s interior. There, at a main trunk or branches, the cut removes entire smaller branches and stems.
Such thinning cuts generally performs major pruning on deciduous shrubs and broad-leaved evergreens.
Depending on the shrub, its growth cycle, and its flowering period, we thin in autumn to spring, or following end of bloom, whenever it occurs.
Step-by-Step Instructions
Shaping and training is a continual process, performed throughout the growing season.
Shrubs grow at dominant buds found at the tips of their branches. By removing these buds, you force the plant instead to begin new growth at a latent bud.
Gather bypass pruners, gardening gloves, splints, stretchy plant tape, and a garden cart for pinched foliage and clippings. Follow these easy steps:
How to Shape and Control Growth of Shrubs
As the shrub leafs in spring, note the strongest branches and overall shape of the plant. Pinch off any leaf buds that later would grow beyond the plant’s desired overall shape and size.
Pinch tender foliage shoots with your finger and thumb to thin the shrub, using care to avoid flower buds.
After foliage matures, pinch or cut branch tips to direct growth. If foliage becomes too crowded for good air circulation, remove one-third of the leaves from the area.
Strip lateral stems on the main branches. This allow sunlights to reach the shrub’s center and maintains air circulation for healthy foliage.
Prune crossing branches, suckers, and weak joints—branches with narrow angles to the main branch or trunk—to maintain proper shape and form.
Train branches to develop and fill areas of the shrub. Use temporary stiff wire or rod splints with plastic stretch tape to bend and train forming branches. After the wood sets its shape in a season, remove the training tape and splints.