If there’s one plant that is synonymous with Rochester, it is the lilac. The Rochester Lilac Festival kicks off our spring every year. Homeowners like to get in on the action too, and lilacs are a common sight in local landscaping. With profuse blooms, a wonderful fragrance, and high deer resistance, it is easy to understand the lilac’s popularity. However, to keep them performing and looking their best, it is essential to know how to prune lilacs.
Why Prune Lilac Bushes
By learning how to prune lilacs you can encourage blooms and maintain your bush’s shape. While any guide to tree pruning stresses that pruning should only be done for the health and safety of a tree, things are a little different when it comes to flowering shrubs. Indeed, most flowering shrubs benefit from regular pruning. Lilacs are no different. Indeed, without pruning, lilacs can start to look ragged and bloom unevenly.
When to Prune Lilacs
First, you need to know when to prune lilac bushes. While many trees prefer winter pruning, this practice would ruin your lilac’s spring show! That’s because your lilac sets next year’s buds right after it blooms. Therefore, trim lilacs immediately after they finish blooming. In this way, you promote strong growth during the season and encourage big blooms for the following spring.
How to Prune Lilacs
Mature lilacs – those 6 to 8 feet tall – need annual pruning. This is your regular maintenance pruning. Your goals are to:
- remove no more than a third of all stems
- maintain a height of 8 feet
- promote even blooming
You do this in three main ways.
First, remove faded flowers. When the blooms are gone, deadhead their remains. This helps the plant put its energy into new growth.
2. Get Rid of Dead or Diseased Stems
Next, prune away dead or diseased stems. Just like with pruning conifers removing dead and diseased material maintains the health of your bush. Dead and damaged stems are entry points for disease and pests. So, get rid of them as soon as they appear.
3. Prune Away Thicker Stems
For lilacs, this means those thicker than 2 inches. Ideally, you want 8 – 12 stems of various ages, all 1 – 2 inches in diameter. This helps with even growth and blooming. Otherwise, older, thicker stems will dominate and blooms will just be at the top.
If pruned regularly in this way, your lilac will perform and grow its best. However, sometimes a bush gets neglected. Severely overgrown lilacs may require rejuvenation pruning.
How to Prune Lilacs: Rejuvenation Pruning
Older and very overgrown lilacs may need more drastic pruning. Called ‘rejuvenation pruning’ this method seeks to ‘restart’ your lilac by cutting back the entire bush to 6 to 8 inches above ground level. This should be done in late winter or very early spring, when the plant is still dormant. Then, apply fertilizer and mulch as the growing season begins. The following spring, prune out skinny growth and keep the strongest stems. Also, you can encourage denser growth by trimming back to branching areas. Within about 3 years your lilac should be filling out and blooming nicely.
Spring Tree Services in Webster NY
Need to get your landscape in shape this spring? Let Arbor Tree Experts know! Established in Webster in 1985 we are a fully licensed and insured tree service in Webster. We offer tree removal, tree pruning as well as stump grinding. Likewise, we can help you choose the best trees for your unique landscape. Contact us for a quote.