This guide walks through all the basics for growing lilacs (Syringa) including how to choose the right lilac for your space, when or if to prune, and how to grow lilacs in containers.
If you love classic flowering plants, also see these tips for growing peonies.
Growing Lilacs (Syringa)
Let’s get into all the basics for growing lilacs. I’ll give you a quick overview of the different types of lilacs and then answer frequently asked questions about pruning, growing tips, growing in pots, and more.
If you grew up somewhere with a big old reliable lilac, you likely have a sentimental attachment to those gorgeous multi-faceted flowers wafting their fragrance through the air. I know I do.
When planted in the right spot, lilacs can live for decades and longer with little or no maintenance.
Lilac | Genus: Syringa
Lilac Growing Guide
Deciduous flowering shrub
• Hardiness zones 3 to 7 (some exceptions)
• Full sun 6+ total hours per day
• Well-draining soil
• Plant with room for root growth and size at maturity
• Non-native but considered non-invasive in cold climates
Shop Online: Naturehills.com has a good selection of lilacs (US shipping).
Non-Native But Not Invasive
While not indigenous to North America, after hundreds of years of growing in Canada and the United States, lilacs have proven to be reliable, low-maintenance plants.
Neither invasive nor aggressive, most do best in colder regions (zones 3 to 7) that provide a winter rest period. Once you’re at zone 9 or higher, you will need to find one bred for those unique conditions. There is more on finding your hardiness zone number below.
Lilacs also play a role in a food web. They are used by various butterfly and moth (Lepidoptera) larvae for sustenance and habitat. The nectar is foraged by pollinators including hummingbirds and bees. This is good. The more our gardens contribute to biodiversity, the better.
Lilacs Can Grow as Trees or Shrubs
The first thing to understand about lilacs is that there are many different types (shapes and sizes) and this matters initially for plant selection and then ongoing care.
There are lilacs that grow as fairly compact 6-foot round shrubs and others that grow as tall, 35-foot trees with plenty of other options in between.
As with any tree or shrub, you should plant it based on its projected mature size to be certain it has the light and space it will need.
12 Species and Many Varieties
The Syringa genus has 12 recognized species and many hybrids, cross-breeds, varieties, and cultivars, providing an array of choices depending on what you want for your garden.
Tips For Choosing a Lilac
With all the choices available, this will help determine which type of lilac is right for your garden.
Ensuring a perennial plant is suited to your winter low temperatures is always step one in the selection process.
Lilacs range from zone 2 hardiness with a few reaching up to zone 10. Many of the cold climate ones are best for zones 3 to 7.
If you are in the United States (lower 48), you can mail order lilacs from Naturehills.com here.
These are just a few examples.
- Common white lilac – Syringa vulgaris var. Alba (zones 2 to 7)
- Dwarf Korean lilac – Syringa meyeri ‘Palibin’ (zones 3 to 7)
- James Macfarlane lilac – Syringa x prestoniae ‘James MacFarlane’ (zones 2 to 7)
- Royalty lilac – Syringa x josiflexa ‘Royalty’ (zones 3 to 8) – late blooming
- President Grevy lilac – Syringa vulgaris ‘President Grevy’ (zones 3 to 7) – fast growing
- Miss Kim lilac – S. Pubescens subsp. Patula ‘Miss Kim’ (zones 3 to 8)
2Suitable for Your Growing Conditions
Your plant hardiness zone is just one factor in plant selection.
From there you want to be sure you can provide the right growing conditions including full sun, well-draining soil, ample room for root growth, and room for the mature lilac plant. There is more on this below.
Do you want your lilac to grow as a shrub in a border, have several grouped together to form a hedge, or simply as one large tree?
This is where selecting the right plant matters: each have their own natural shapes.
- Border shrub: Pubescens subsp. Patula ‘Miss Kim’ (lilac) – grow mostly as shrubs (zones 3 to 8)
- Hedge: Persian lilac – S. × persica L. (syn Syringa protolaciniata) – (zones 3 to 7)
- Tree: Syringa reticulata subsp. amurensis – grow 25-30-feet tall (zones 3 to 7)
How big do you want it and do you have the space? Factor in how other surrounding trees and shrubs will also continue growing.
Size is relative when it comes to lilacs. The so-called dwarf or compact varieties average 6-feet around. Others max out around ten feet tall. And, as mentioned, there are options all the way up to 35-feet tall.
When would those flowers really stand out?
There are lilacs that bloom at various times from mid-spring right through to midsummer.
Some varieties can also bloom a second time in the same season including Bloomerang® Lilac Syringa x Purple Syringa x ‘Penda’ , a dark purple cultivar by Proven Winners.
6Flower Type and Fragrance
While purples, also called ‘true lilac’, are the classic familiar bloom colors, there are plenty of other options including white, pinks and magentas, shades of violet and blue, and various bi-colored options. And these may be single, double, or ruffled in formation.
Fragrance ranges from gentle to knock-your-garden-socks-off bold. It’s up to you what is desirable.
Cut Flowers | If you are growing for cut flowers, either for your home or a business enterprise, you may look for certain traits including lilac flowers that hold their shape after cutting, specific bloom styles and size, particular colors, stem strength, fragrance and more.
7Deer & Pest Resistance
A hungry deer with few options is probably going to eat anything it can, but there are a number of lilac varieties that deer will turn down if there are other food options available. One example is Syringa x chinensis ‘Saugeana’ – Persian lilac.
If issues like powdery mildew (Microsphaera syringae is a fungal pathogen affecting lilacs) is an ongoing headache in your area, there are certain lilac varieties known for the mildew resistance which is often listed as a selling point on plant tags.
Frequently Asked Questions
What are some top tips for growing lilacs?
First, you need the right plant in the right place.
This means choosing a lilac suited to your growing zone and conditions.
They like non-acidic, well-draining soil with ample room for root growth, and most need at least 6-hours of full sun per day. There are a few that are tolerant of part-shade.
A great feature is how low maintenance lilacs can be. Once planted, many can just be left to grow.
If you do feel yourself reaching for the pruners, never cut or trim without a specific purpose (more on this below) and only fertilize if there is a known deficit with the soil nutrition or you are growing your lilac in a container.
When should I prune my lilac? What’s the best time to trim lilacs?
Lilacs can live long healthy lives without ever being pruned. Pruning does not trigger blooms and is not required for the plant to grow.
That said, there may be circumstances that warrant it.
First, it’s important to distinguish between deadheading and pruning.
Deadheading Versus Pruning
Deadheading—the removal of finished flowers—is commonly recommended, both to clean up the plant and make room for new growth. This also prevents seed formation so the plant uses its energy elsewhere.
For lilacs, deadheading (optional) should be done soon after flowering before new buds start forming.
Deadhead old flowers by clipping their stems just above a leaf set, and otherwise step away from the pruners.
Pruning—the removal or cutting back of stems or branches on shrubs, vines, or trees—is always done with a specific purpose in mind and your lilac may never need it.
If you are uncertain, leave it alone.
It can take years of gardening to develop an eye for pruning. No hurry.
Remove Any Dead, Damaged, or Diseased Parts
One exception (for all plants): you can and should always remove any dead, damaged, or diseased growth.
Some lilacs trees will get branches crossing and rubbing against each other and that should be dealt with as well.
From there, we only prune to control the shape and size of the plant—if necessary, working with the basic shrubby or tree-like nature of the specific plant.
Cutting Back Old Shrubby Lilacs
Some shrubby old lilacs get non-flowering stems after many years and may be candidates for ‘renewal pruning’ where a portion of the stems (perhaps 1/3 of all growth each year) are cut right back within a few inches of the ground to trigger fresh growth. Look it up if you think your shrub might benefit from this.
Keep in mind that any buds you remove would have formed next year’s flowers. It’s not a problem to remove budding stems—if you have a good reason to—but it is something to be mindful of since we are normally growing these babies for their blooms.
And always start with the question: what is the purpose of the pruning?
How do your propagate lilacs?
This describes the four basic ways to propagate lilacs: division, cuttings, layering, and from seed.
When is the best time to plant lilac? Spring or Fall?
The common advice is always to plant in fall and theory is that this gives the roots time to establish without much risk of drying out.
Personally, I always plant at purchase time which is often spring.
I’d much rather get the plant in the ground and tend to it there than try to keep it happy in a container for months before finally planting it. Waiting until fall just seems like I’m delaying growth.
Bottom line, plant it during the growing season when you’re ready and provide the care it needs (consistent water while roots get established).
Can I grow lilacs in pots?
Yes. Choose a smaller dwarf or shrub variety that will not require a huge amount of root space and start with the largest pot you can provide.
Use container mix suitable for shrubs.
You may want to set up the pot on a plant trolley like this to help move it as needed.
Be prepared to protect the plant over the winter, following the overwintering instructions here.
It is also likely that you will need to fertilize your potted lilac annually with a product like this.
How old does a lilac have to be before it blooms?
If buds are there, blooms are on the way, either this year or next.
If you buy a lilac at a plant nursery in a container and it has matured enough to have some stems with buds, if it’s not in bloom already, it may flower soon.
Do not add fertilizer thinking that will help: it doesn’t. Time and sunlight help.
I notice some gardeners mention their lilacs grown from cuttings may take a few years to flower. Lilacs grown from seed—the slowest propagation process of all—take even longer.
I assume this is because the plant needs to time to mature enough to form stems and buds.
What kind of lilac bush do I have?
There are numerous lilacs and identification can be tricky beyond the common lilac (Syringa vulgaris).
The more you can observe about the plant, the easier the identification process.
Sometimes the species type is obvious but it’s the specific subspecies or variety/cultivar that is hard to decipher.
If yours is an ID challenge, get photos of the whole plant, the base of the plant (one stem or several), the leaves (individually and how they attach to the stems), and the flowers (whole flowers and close up).
Try putting the images in google image search to get a match, use a plant ID app on your phone, ask in a garden forum, or ask at a local plant nursery.
My lilac started to bloom and then the flowers turned brown? What’s wrong with it?
This can happen for a few reasons.
Was there a late frost or cold snap that may have frozen or wind-burned the flowers?
Are there any other signs of disease or distress?
The more you can describe about the change, the more likely to find an answer.
Clear photos (whole plant and closeup) and a concise description in a garden forum should help.
Watch Lilac Videos
Choose the right lilac for your growing zone and specific conditions.
Sun, well-draining soil, and room for root growth are important both for optimum flowering and growth.
Pick a variety that suits your purpose for landscaping (size and style of shrub, hedge, or tree) and/or specific flowers, colors, fragrance, and bloom times.
Deadheading—the removal of finished flowers—is optional and can improve the appearance. Do it immediately after blooming before new buds have formed.
Pruning is optional and should be done for a specific purpose either to remove dead, damaged, or diseased stems, help shape the plant, or give an older lilac shrub a reset.
Propagation by division is easiest if your lilac is providing shoots from the roots. Otherwise, growing from cuttings or layering are the next best options. Growing from seed is for patient, dedicated garden geeks only (and I say this fondly).
~Melissa the Empress of Dirt ♛
Empress of Dirt
Reader’s favorite tips and tutorials on various topics compiled into handy downloadable ebooks.