Tips on how and when to cut back lilacs to keep your shrub healthy.
Besides resulting in a bonanza of blooms each year, pruning lilacs(Syringaspp.
)helps makelilac shrubsmore shapely, strong, and healthy.
Credit:Marty Baldwin
So grab your shears and read on to learn how and when to prune lilacs properly.
Left unpruned, mature lilacs become choked with old wood and deadwood and produce few flowers.
They also become wildly overgrown and unruly.
Credit: Lynn Karlin
Also, as lilac shrubs grow, the lower parts become shaded by the canopy above.
That means they won’t get as much sunlight and will begin to lose their leaves.
When to Prune Lilacs
Timing is everything.
Heres when to take the shears to your shrub.
Types of Pruning for Lilacs
There are two types of pruning for lilacs.
The pruning you do depends on the age and condition of the lilac.
Deadhead lilacs annually as soon as flowers fade.
Cut off the old flower cluster at its base.
Removing old blossoms lets the plant put more energy into growing new buds and stems rather than producing seeds.
Rejuvenation pruningalso called hard pruningcanrevive an old, overgrown lilac that has been neglected.
Fertilize your lilacafter you do a rejuvenation pruning to help fuel new growth.
Use abalanced (10-10-10) fertilizer, preferably slow-releasegranular fertilizer, following the product instructions.
Borer infestations can be fatal.
Keep an eye out for borer holes with a sap flow and wilted leaves that turn reddish-brown.
You should also look for swollen areas on branches.
Some years your lilacs will burst with blooms, and other years they wont.
Lilacs do best in cooler climates ofUSDA Zones 3 to 7.
Lilacs also do poorly in humid climates because theyre prone topowdery mildew.
University of NebraskaLincoln, Institute of Agriculture and Natural Resources.
Lilac Borer and Ash Borer.
