Transform your lilac into a vigorous attractive shrub
For the absolutely perfectly shaped lilac bush you need to prune them
each year. Pruning is a very important part of growing and caring for
Lilacs. While some varieties only grow 4 to 8 feet, others can reach up
to 30 feet tall. Many will grow in excess of 10 feet. Pruning will not
only help with shape and appearance, but also impact health and vigor
and the profusion of flowers.
There are right and wrong ways to prune a lilac bush. There is also
a right and wrong time. Most importantly, prune or trim back your bush
immediately after they are done blooming. Make sure to remove the spent
bloom with your clippers. This will keep the plant from growing seeds
and encourage creation of next year’s buds. Next year’s flower
bud develops early even though you do not see it. I have seen inexperienced
gardeners trim off the next year’s flowers with one pass of the
hedge trimmer. By the way, I do not recommend using hedge trimmers as
it gives a too sheared appearance. Lilacs are not hedges.
Lilac bushes should be pruned and maintained each year for a well-shaped
healthy plant. The plants should be full looking, yet not overly bushy.
If the plant is too bushy, the inner leaves do not get sun and air circulation,
making it an easy target for plant disease. First clip old dead flowers
at the base. Pruning should be done immediately after the flowers have
died off. Cut suckers and shoots at or near ground level or where it comes
out of the main trunk. Leave a few strong and healthy new stalks each
year, especially if you are planning to trim back old wood. Trim larger
stems from the center of the bush to increase ventilation. It will also
afford more room for newer shoots on the outside of the plant to develop.
Trim back any branches that stick out from the main bush and are not appealing
to you. Topping the bush is not recommended. A flat top is not an appealing
lilac to most lilac lovers. A slight rounding to the top looks best. In
trimming and pruning your bushes, remember beauty is in the eyes of the
beholder. If you like a tall bush let it grow tall. If you prefer a wide
bush, encourage shoots that have spread out from the main bush.
Pruning Mature Lilacs
Far too often you see a lilac that hasn’t seen pruning since it
was planted. Plants that have been let go this long only produce a few
sparse blooms 10 feet in the air and old trunks look decidedly unhealthy.
One way to renew a large, overgrown lilac is to cut the entire plant back
within 6 to 8 inches of the ground in late winter (March or early April).
This severe pruning will induce a large number of shoots to develop during
the growing season. In late winter of the following year, select and retain
several strong, healthy shoots to form the shrub framework and remove
all the others at ground level. Head (cut) back the retained shoots to
just above a bud to encourage branching. I proceed in this manner when
a plant has reached that point of no return and drastic measure are called
A second way to prune old lilacs is to cut back the overgrown shrubs
over a three-year period. Begin the procedure by removing one-third of
the large, old stems at ground level in late winter. The following year
(again in late winter), prune out one-half of the remaining old stems.
Also, thin out some of the new growth. Retain several well-spaced, vigorous
stems and remove all the others. Finally, remove all of the remaining
old wood in late winter of the third year. Additional thinning of the
new shoots should also be done. Since lilac wood needs to be 3 or more
years of age before it blooms, this pruning method should allow you to
enjoy flowers every spring. This is my usual mode of rejuvenation pruning
lilacs. It provides a smoother transition for the plant and often more
importantly a smoother transition for the lilac’s owner…
When properly pruned, an old, overgrown lilac can be transformed into
a vigorous attractive shrub within a few years. Once rejuvenated, pruning
should be a regular part of the maintenance program for lilacs. The shrub
can be kept healthy and vigorous by removing a few of the old branches
every 3 to 5 years, and there is no good reason the plant shouldn’t
live for another century.
Read an informative article about pruning your lilacs
to choose lilacs
What to look for when choosing a lilac for your garden
Instructions for how to obtain successful lilac growth
The Helpful Gardener brings the pleasure of gardening to your home. Here
you will find our entire collection of Lilac
care articles collected in one spot.