How to Grow Lilacs: A Goebbert’s Guide
There are a few scents that signal spring has truly arrived in the Chicago suburbs, and the sweet perfume of lilac is one of our absolute favorites.
It’s a fragrance that brings back memories: of grandma’s garden, of warm breezes carrying that familiar scent down the block, of cutting a few blooms to bring indoors. Lilacs are more than just beautiful; they’re a tradition.
Here at Goebbert’s, we’ve been helping families grow these classic shrubs for generations. They are refreshingly easygoing. Give a lilac a sunny spot, good airflow, and a simple prune once a year, and it will reward your family with beautiful, fragrant blooms for decades to come.
Let’s get growing!
Choosing Your Perfect Lilac
Not all lilacs are the same! Picking the right one is like choosing a new family member. It’s all about finding the right fit for your home and yard. Let’s break down the options so you can find the lilac that will make you smile every spring.
For Classic Fragrance & Privacy: Common Lilac (Syringa vulgaris)
This is the lilac you probably remember from your childhood. Common lilacs grow tall (often 8-15 feet) and are known for their powerful, classic perfume. They are fantastic for creating a living privacy screen along a fence line or as a beautiful backdrop for your other garden plants. Their dense, leafy growth after blooming provides great summer coverage.
For Show-Stopping Blooms: French Hybrids
If you want your neighbors to stop and stare, French hybrids are for you. These varieties produce enormous, dense flower clusters (called trusses) in a stunning array of colors, from deep magenta and painterly lavender to pure white and soft pink. They bring a touch of elegance and drama to any garden bed.
For a Unique Focal Point: Tree-Form Lilac
A tree-form lilac is simply a lilac pruned into a small, single-stem tree standard. This elevates the blooms to eye level, creating a stunning accent for a courtyard, entryway, or small garden. It’s a real conversation starter and a clever way to add height and fragrance without taking up a lot of ground space.
For Smaller Spaces & Repeat Blooms: Dwarf & Reblooming Lilacs
Think you don’t have room for a lilac? Think again!
- Dwarf Lilacs like ‘Miss Kim’: This popular variety stays much more compact, typically around 4-5 feet tall and wide. It has a tidy, rounded shape, clean foliage, and a wonderfully spicy-sweet fragrance. It’s perfect for foundation plantings or near a patio where you can enjoy the scent up close.
- Reblooming Lilacs like ‘Bloomerang’: Why have one show when you can have two? The Bloomerang® series offers a heavy flush of flowers in spring and then “reblooms” from mid-summer through fall. These compact shrubs are workhorses, extending the fragrance and beauty for months. They’re ideal for containers or small garden beds.
The Short Version – Lilac Care
- Sun: 6+ hours daily.
- Soil: Well-drained.
- Water: Deeply but infrequently once established.
- Feed: Very lightly, if at all. Compost is best.
- Prune: Right after spring bloom. Never in fall or winter.
- Airflow: Give it space to breathe.
Finding the Right Spot: Sun, Soil, and Space
Lilacs are tough and dependable, especially in our windy Illinois springs. But giving them the right home from the start is the key to years of effortless blooms.
Sun, Sun, and More Sun: Lilacs are sun worshippers. They need at least six hours of direct, unfiltered sunlight each day to produce the maximum number of flowers. If your lilac isn’t blooming, lack of sun is the most likely culprit.
Well-Drained Soil: Lilacs hate “wet feet.” They need soil that drains well and won’t stay soggy after a rain. If you have heavy clay, it’s a good idea to amend the planting area with compost to improve its structure and drainage.
A Touch of Sweetness: These shrubs prefer soil that is neutral to slightly alkaline (a pH around 7.0 is perfect). Our local soils are often a great match.
Give It Room to Breathe: Good air circulation is crucial for keeping lilac leaves healthy and preventing powdery mildew. Avoid crowding them against a wall or other dense shrubs. Your future self will thank you for the healthy foliage!
Planting Your Lilac for a Strong Start
Planting in early spring or early fall gives your new shrub the best chance to get established before the stress of summer heat or deep winter cold. It’s a simple process that pays you back for years.
- Dig the Right Hole: Dig a hole that is twice as wide as the nursery pot but only as deep.
- Check the Depth: Gently place the plant in the hole. The top of the root ball should be level with or even slightly above the surrounding soil. Planting too deep is a common mistake!
- Backfill and Water: Fill the hole back in with the native soil. Water slowly and deeply, allowing the water to soak in and settle the soil around the roots. This encourages roots to grow down, not out.
- Add a Blanket of Mulch: Apply a 2-inch layer of organic mulch (like shredded bark or compost) around the base of the plant, but be sure to pull it back a few inches from the main stem. Mulch helps hold in moisture and keeps weeds down, but piling it against the stem can lead to rot.
For the first two years, your main job is to help your lilac build a strong root system. Water deeply whenever the top few inches of soil feel dry, and keep the area free of weeds that compete for water and nutrients.
The Golden Rule of Pruning Lilacs
If you remember one thing about pruning, make it this: Prune lilacs right after they finish flowering.
Lilacs form next year’s flower buds on old wood during the summer. If you prune in the fall, winter, or early spring, you’ll be cutting off all of next year’s beautiful blooms!
Your Post-Bloom Pruning Checklist:
- Renew the Shrub: Every year or two, select one to three of the oldest, thickest stems and cut them all the way down to the ground. This renewal pruning encourages vigorous new growth from the base, keeping the shrub youthful and productive.
- Shape It Gently: Aim for a natural, open, vase-like shape. Thin out any crossing branches or weak stems to allow sunlight and air to reach the center of the plant.
- Deadhead (If You Want): Snipping off the spent flower clusters makes the plant look tidier, but it’s completely optional and won’t affect next year’s bloom.
- What NOT to Do: Never shear a lilac into a tight ball or formal hedge. This ruins its natural form and often removes the flower buds.
Ongoing Care: A Little Goes a Long Way
Once established, lilacs are wonderfully low-maintenance.
- Watering: Mature lilacs are quite drought-tolerant. They’ll appreciate a deep watering during extended dry spells, but don’t overdo it. Always water at the base of the plant in the morning to keep the leaves dry.
- Feeding: Lilacs are very light feeders. In fact, over-fertilizing is a common cause of poor blooming. Too much nitrogen will give you lots of lush green leaves but very few flowers. The best approach is to top-dress the soil around the plant with a layer of compost each spring. That’s it!
Lilacs rewards attention, not obsession. With these simple steps, you can cultivate a beautiful shrub that will be part of your family’s story for years, filling your yard with the unforgettable scent of spring.
Lilac Growing Guide PDF
Design Ideas for Your Garden
Lilacs play well with others! Here are a few of our favorite ways to use them at home:
- A Fragrant Welcome: Plant a dwarf lilac like ‘Miss Kim’ near your front door or patio. The scent will greet you and your guests.
- A Living Fence: Use a row of taller common lilacs along your property line for a beautiful, fragrant screen in spring that turns into a dense green wall in summer.
- Perfect Partners: Pair a lilac with a small ornamental tree, like a Japanese Maple. The maple can provide a little dappled shade during the hottest part of the summer.
- Layer the Seasons: Underplant your lilac with spring-flowering bulbs like daffodils or tulips for an early pop of color. For summer interest, edge the bed with low-growing perennials like catmint (Nepeta), which complements the fading lilac blooms beautifully and attracts pollinators.
Troubleshooting Common Lilac Issues
Even the toughest plants can have an off day. Here’s how to solve the most common problems with confidence.
- Problem: Few or No Flowers
- Causes: Not enough sun, pruning at the wrong time (too late in the season), or too much nitrogen fertilizer.
- Fix: Ensure it gets 6+ hours of sun. Prune ONLY within a few weeks after it flowers. Stop using high-nitrogen lawn fertilizer near the plant and switch to a simple compost mulch.
- Problem: White, Powdery Film on Leaves (Powdery Mildew)
- Causes: Poor air circulation and damp leaves, especially from overhead watering at night.
- Fix: Water only at the base of the plant in the morning. If the shrub is very dense, thin out a few branches after it blooms to improve airflow.
- Problem: Shoots Popping Up from the Ground (Suckers)
- Causes: This is a natural habit for many lilac varieties.
- Fix: Simply prune these suckers off as cleanly as you can at ground level whenever you see them. This keeps the plant looking tidy.
- Problem: Scorched or Wilting Leaves in Summer Heat
- Causes: A sudden heatwave is stressing the plant.
- Fix: Give the plant a long, deep soak at the base. A healthy layer of mulch will help keep the roots cool and moist. Avoid stressful activities like pruning or transplanting during extreme heat.