Why Isn't My Lilac Blooming? 6 Common Reasons and Easy Fixes
Is your lilac all leaves and no flowers? Here are the likely reasons it's not blooming, and how to fix it.
Gardening Know How
Lilacs are magical shrubs. For most of the year they sit innocuously, blending in with the greenery. But for a couple weeks in May, they explode into clusters of flowers that give off one of the most intense and enchanting scents you could ever hope to find in a garden.
Those couple of weeks make the whole year worthwhile, so it's incredibly unnerving to watch May tick away with no flowers in sight. What could be keeping your lilac from blooming? There are a few possible causes. Let's dive deeper into this important aspect of lilac care.
Reasons a Lilac Bush Won't Bloom
There are several possible reasons for no flowers on a lilac bush. Here are the most likely causes, and an explanation of how to correct them.
1. Improper Pruning
If your lilac isn't flowering the most likely culprit is improper pruning. When pruning lilacs, timing is key. Lilacs bloom on last year’s growth, so it’s important to prune them immediately after they’ve finished blooming in spring. If you wait until summer, fall, or winter to prune a lilac, you could be removing buds that would otherwise bloom the following spring.
Try to do just a light pruning right after the spring bloom. A hard prune will delay the next bloom, so just thin out the oldest and thickest branches, and trim inner branches to allow sunlight to penetrate through the bush.
2. Age
How long have you had your lilac bush? Is it big enough that it's really more of a tree by now? A lilac’s best blooming takes place on younger wood, so if your bush is mostly old growth there's simply less of a percentage of places for flowers to bloom. You may need to do a rejuvenation pruning and wait two or three years to let it come back to full bloom.
3. Not Enough Sun
Lilacs want full sun, which means about six hours a day of sunshine. Even if your lilac is in partial shade, it’s not going to do as well, so be sure other trees aren’t blocking its sun.
4. Improper Watering
Mulching around your lilac helps to control weeds and keeps the roots from drying out. In dry weather, it’s important to water a lilac regularly. However, lilacs thrive in well-draining soil and don’t like soggy, wet roots.
5. Too Much Fertilizer
If you’re fertilizing your non-blooming lilac, stop! Over-fertilized lilacs will grow lots of luscious greenery, but won’t give you the flowering you’re hoping for. Lightly fertilize lilacs once in the spring, then leave it at that. If you’re regularly fertilizing other plants or fertilizing a nearby lawn, your lilac may be getting more food than it wants. Adding phosphorus, like an application of bone meal, to your lilac’s soil will help.
6. Pests
Lilacs can be subject to scale insects and borers. Examine your bush’s leaves and stems to determine whether you need to do a renewal pruning. Cutting away the problem areas will usually resolve the problem.
Lilac Care Essentials
What if My Lilac Never Flowers?
There are several lilac cultivars that won’t bless you with blooms for five or more years after planting. If you have a young lilac, patience may be your only solution until the bush matures and grows strong enough to produce blossoms.
Even dwarf varieties can take up to a couple years to work up a bloom, so nurturing and providing the proper support for your lilac while it’s young will pay off later.
How and where you initially place your lilac bush is the best insurance for beautiful blooms, so plan ahead for a sunny, well-drained spot, and stay on top of spring pruning for beautiful, fragrant lilac blooms every year.
