From April to June, lilacs are a magnificent floral spectacle – a miracle of nature! But if you want these gorgeous shrubs to fill with blossoms every year, they need some tender loving care in late winter to early spring. You need to get them ready to bloom profusely, and attract lots of butterflies and pollinators to add even more color and beauty to your garden!
In fact, if you have a mature lilac, you might have noticed that, yes, it does blossom punctually, but there may be gaps in the wall of flower you expected; and that’s what we want from Syringa shrubs, a waterfall of cone shaped panicles packed with four-petaled blooms…
So, what can you do in late winter and early spring to make sure your lilacs will overwhelm you again with their display this year? Just follow me…
1: Keep Your Lilacs Tidy
First of all, a very simple thing: keep your lilacs tidy at the base. Clear leaves and all organic matter from under your shrubs. You don’t want to have a breeding ground for bacteria, fungi and pests during winter, as they will multiply and thrive as soon as spring arrives, attacking your prized garden beauty.
2: Keep Your Lilac’s Roots Warm and Protected
If you didn’t do it in fall, when you should have, do apply a good layer of mulch (2 inches, or about 5.0 cm minimum) at the base of your lilacs, so their roots are warm, and you will preserve nutrients in the soil – they will need them when spring comes!
Spread mulch to the drip line, which is the furthest point your lilac shrub reached in the past season. On the other hand, do not apply mulch straight against the base of the base of the main stems; leave a small gap so they don’t get wet. Next…
3: Water Your Lilacs Correctly in Late Winter and Early Spring
It is easier to irrigate lilacs when the season is in full swing; they need plenty of water and you don’t run many risks, especially if they are adults. But in winter and early spring things are a bit more difficult.
In winter, only water lilacs if the weather is dry, these shrubs are fully dormant during this season, and all they need is a bit of residual moisture in the soil; so, usually rainfall is enough in most regions.
As spring starts, you should adapt watering to rainfall, of course, but the key signal that you should move to fully regular irrigation is when you see new buds develop. This means that your lilac is coming out of dormancy, and it will be thirsty.
Be very particular with young lilacs, they will not tolerate drought at all, but in all cases, always avoid overwatering, and always irrigate from below (you don’t want wet branches where diseases can set in).
4: What Shall You Do with Lilac “Babies”?
Lilacs tend to spread… As they grow, you will notice little shrublets (they are suckers, technically) coming out of the ground next to them. This can happen from spring to fall, but late winter is a good time to deal with them. And why? Because you can see them clearly, and because they are still dormant. But what can you do with these Syringa “babies”? You have three options:
- Leave them there, if you wish your lilacs to spread and propagate.
- Cut them down; when they are young and before they leave dormancy it’s a good time to cut them to ground level with loppers.
- Propagate them; maybe you want lilacs somewhere else in your garden? Then, wait for early spring when they come out of dormancy, dig down next to the shrublets, then follow the instructions in the next section.
Of course, you can pick and mix these three options!
5: Propagating Your Lilacs in Early Spring
Early spring also is a good time to propagate your lilacs, but not in all possible ways, in fact, just one, and it is by suckers, or the shrublets we talked about a minute ago. These can grow at some distance from the main shrub, and they come straight from its roots. How can you do it? It’s very simple!
- Find a strong and healthy sucker growing away from the main shrub; you don’t want to damage it.
- Use a spade to dig around the sucker, starting at least 6 inches (15 cm) away from the shoot.
- Now you can see the roots that connect the sucker to the main root, cut them with pruners. Use a sharp spade to cut the sucker from the main root of the parent lilac shrub.
- Dig up the sucker with some attached roots.
- Transplant it straight away!
This will, of course, fill your garden with more shrubs, and so more lilac flowers!
6: When and How to Fertilize Your Lilacs Early in the Season
Let’s be clear, you should not fertilize your lilacs in late winter. Hold on to early spring, when they are coming out of dormancy. You don’t want to give your flowering beauties the “wrong signal” and promote new growth when it is still too cold for them.
But how can you do this? Well, at this stage, they need a balanced slow-release fertilizer, with NPK 10-10-10. You don’t want to promote new blooms too early in the season with a high phosphorus product.
You can also use compost, of course, scattering a 1-inch layer, (2.5 cm) at the base of your lilac shrub.
Whether you use granular fertilizer or compost, do not dig them in. Allow the fertilizer to seep into the soil and do not disturb the roots of your lilac.
7: Improve Drainage So Your Lilacs Have “Dry Feet”
Fall and winter are usually wet seasons, and the heavy rainfalls take their toll on the drainage of the soil. Spring too can see lots of clouds and rain in many parts of the world, so… Late winter is a good time to act!
An inch (2.5 cm) of coarse sand scattered at the base of your lilac shrubs should suffice for most soils, making sure you reach the drip line. If drainage is really poor, then add another inch (2.5 cm). But if it is heavy clay, use gypsum instead (you can add sand too, but without it, it won’t work).
8: Think about Your Lilac’s Health!
With all the rains and the heavy weather that come with winter, your lilacs can catch diseases, mainly fungi and bacteria in this season. And because we are locked indoors, we may not have noticed them!
On the other hand, when lilacs have no leaves (or small buds), so in late winter and early spring, it is easier to check for infection! When the foliage and blooms are so dense, it is harder – you will agree…
The best way to treat your lilac shrubs is to use neem oil, which hasamazing antibacterial and antifungal properties – and it is very cheap to boot!
- Add 1 to 2 teaspoons of neem oil per liter of water in a spray bottle or tank.
- Add a dash of natural liquid soap.
- Shake well.
- Spray thoroughly.
Repeat every 2 weeks as necessary or after heavy rains. Most often a single application is enough to kill bacteria and fungi.
And now, the final and big chore to get your lilacs to blossom like the garden queens they are later in the season…
9: Pruning Lilac Shrubs in Late Winter and Early Spring
Late winter and early spring are not the time for your lilac’s main pruning, that’s after they have blossomed, but there’s some tidying up to do now…
- Cut dead and very sick branches.
- If your lilac is really overgrown, you can cut some branches, but go light with it!
- If you have very tall and old branches, you may have noticed that last year, they only blossomed at the top. So, if you haven’t done it already, you can cut these back; it will promote new growth.
- In case your lilac has spread too far, you can reduce some of the branches, and this is only a matter of space in your garden.
In any case, late winter and early spring pruning is a light job for lilacs, you want to tidy them up, keep them healthy and in size if necessary, nothing more. And the reason? Lilacs flower on old wood, which means that they start producing new buds very early on, and if you cut them early in the season, you get rid of “flowers to be” too.
“But how about if I cut new branches?” you may ask… Well, in late winter and early spring, all of them are old, because new ones will start later…
So, be light with pruning now, or you will be guilty if your lilac’s flowers disappoint you!
Late Winter and Early Spring: Help Your Lilacs Now and Massive Blooms Will Come Soon – Very Soon
Lilacs are early bloomers, so this transition season is essential to get them to flower profusely, and now you know what you need to do. Careful with pruning, time feeding them well, and then a few other simple chores, and your garden will soon fill with jaw-dropping blossoms, and butterflies, and bees…
Written By
Amber Noyes
Amber Noyes was born and raised in a suburban California town, San Mateo. She holds a master’s degree in horticulture from the University of California as well as a BS in Biology from the University of San Francisco. With experience working on an organic farm, water conservation research, farmers’ markets, and plant nursery, she understands what makes plants thrive and how we can better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially organic gardening, houseplants, and growing plants in a small space.