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Planting and Growing Lilac Bushes

purple Yankee Doodle Lilac flowers

Huge blooms, wonderful scent.

Image Credit:
Wally Patrick
Botanical Name
Syringa spp.
Grown as
Perennial
USDA Zones
3a
3b
4a
4b
5a
5b
6a
6b
7b
Toxicity
Non-toxic
Sun Exposure
Full Sun
Partial Sun
Water Needs
Moderate
Height
6-10 feet
Spread
6-10 feet
Soil pH
Neutral
Bloom Time
Spring
Summer
Flower Color
Blue
Pink
Purple
Red
White
Yellow
Special Features
Container-Friendly
Cut Flower
Fragrant
Attracts Butterflies
Attracts Hummingbirds
Attracts Pollinators
Deer-resistant
Rabbit-resistant
Resilience
Cold Hardy
Drought-Tolerant
Plant Type
Shrubs and Bushes
Written By: Catherine Boeckmann Executive Digital Editor and Master Gardener

Lilacs truly smell like spring! Lilacs are among the most carefree spring-flowering shrubs and provide a sweet, haunting fragrance, too! Learn how to plant, grow, and prune your lilacs.

Lilacs, said to symbolize the joy of youth and associated with spring’s awakening, are hardy, easy to grow, and low-maintenance. Although they can reach heights of 5 to 15 feet (or more), depending on the variety, the ideal lilac shrub produces flowers at eye level—all the better for enjoying their sweet fragrance.

The common lilac, Syringa vulgaris, is well loved for its toughness, reliability, and fragrance. In fact, lilacs are so tough that they can grow for 100+ years, often outliving the homes they were planted around. The fragrant flowers are good for cutting and are attractive to butterflies.

While the blooms are usually lilac/purple in color (from very pale to very dark), there are also lilac varieties in white and cream and even pink and yellow. Individual flowers can be single or double.

In northern states, lilacs bloom for about 2 weeks from mid- to late spring. However, there are early-, mid-, and late-season lilacs, which, when grown together, ensure a steady bloom for at least 6 weeks.

Planting

When to Plant Lilacs

  • Like most shrubs, lilacs can be planted in either spring or fall, although the latter is preferred.

Where to Plant Lilacs

Lilacs thrive in fertile, humus-rich, well-draining, neutral to alkaline soil (at a pH near 7.0). If your soil is in poor condition, mix in compost to enrich it. (Learn more about soil amendments and preparing the soil for planting.) Choose or prepare a site that drains well. Poor drainage or pooling water can cause “wet feet,” potentially leading to root rot, stunted growth, and/or failure to flower. Test soil drainage by digging a hole 8 inches in diameter and 12 inches deep. Fill it with water; if it does not drain within an hour, choose another spot.

For the best blooms, lilacs should be planted in full sun, which is defined as at least 6 hours of sunlight each day. Given less, they will not flower as well. 

How to Plant Lilacs

  • If you’re lucky, a friend will give you a sucker, or offshoot, of the root system of one of their plants. The sucker will look pathetic at first, but dig a hole, backfill it with soil, and stick the sucker in. Then, water and wait. In 4 or 5 years, you’ll be rewarded with huge, fragrant blossoms.
  • Transplanting nursery-bought lilacs is also easy. If it’s container-grown, spread out the roots as you settle the plant into the ground; if it’s balled or burlapped, gently remove the covering and any rope before planting. Set the plant 2 or 3 inches deeper than it grew in the nursery and work topsoil in around the roots—then water in. Then, fill in the hole with more topsoil.
  • Space multiple lilac bushes 5 to 15 feet apart, depending on the variety.

Growing

  • Each spring, apply a layer of compost under the plant, followed by mulch to retain moisture and control weeds.
  • Water during the summer if rainfall is less than 1 inch per week.
  • Lilacs won’t bloom if they’re overfertilized. They can handle a handful of 10-10-10 in late winter, but no more.
  • After your lilac bush has finished blooming, spread some lime and well-rotted manure around the base. Trim the bush to shape it and remove suckers at the same time.

How to Prune Lilacs

  • Lilacs bloom on old wood, so it’s critical to prune in the spring right after they bloom. If you prune later in the summer, you may be removing the wood. Note: If your lilac flower clusters are getting smaller over a few years, it’s time to prune!
  • Every year after bloom, remove any dead wood. Prune out the oldest canes (down to the ground). Remove the small suckers. Cut back weak branches to a strong shoot. Cut back tall canes to eye height.
  • The ideal lilac shrub has about 10 canes. If your lilac is old and in really bad shape, remove one-third of the oldest canes (down to the ground) in year 1, half of the remaining old wood in year 2, and the rest of the old wood in year 3. Another option for old lilacs is to chop the whole thing back to about 6 or 8 inches high. It sounds drastic, but lilacs are very hardy. The downside to this option is that it takes a few years to grow back. The upside is less work and more reward, as the lilac will grow back, bursting with blooms.
  • It must be recognized that severe pruning results in the loss of blooms for 1 to 3 years. For these reasons, a wise pruning program aims to avoid severe and drastic cuts by giving the bushes annual attention.
  • Good Sucker Sense: Gertrude Jekyll, the 19th-century no-nonsense English horticulturist (1843–1932), advocated a strenuous exercise: “When taking away suckers … it is better to tear them out than to cut them off. A cut, however close, leaves a base from which they may always spring again, but if pulled or wrenched out, they bring away with them the swollen base.”

Pests and Problems

  • Prone to attack by slugs and snails.
  • Powdery white mildew may appear after a summer of hot, humid weather. It may be unsightly, but it does no harm. Ignore it.

Types

For early flowers, try Syringa x hyacinthiflora hybrids; they bloom 7 to 10 days before S. vulgaris. Its fragrant blooms attract butterflies and hummingbirds.

The most common and fragrant lilacs are of the S. vulgaris variety:

  • Try ‘Charles Joly’, a double magenta flower, an early bloomer.
  • Mid-season lilacs include ‘Monge’, a dark reddish purple, and ‘Firmament’, a fine blue.
  • Late-season beauties include ‘Miss Canada’, a reddish-pink, and ‘Donald Wyman’, a pink-purple flower.

Uncommon types/varieties include … 

  • S. x ‘Penda’ Bloomerang Purple: flowers in spring, pauses, then flowers again from midsummer through fall.
  • Although common lilacs love cold weather, a few thrive as far south as Zone 8, including cutleaf hybrid S. x laciniata, with fragrant, pale lavender flowers, and S. pubescens ssp. patula ‘Miss Kim,’ with pale, lilac-blue blooms that fade to white.

Small Lilacs
For gardeners, especially those in urban spaces, who just don’t have the room for the traditional larger lilac, there are compact varieties! They’ll even grow in a container on your patio or balcony.

  • ‘Baby Kim’ grows only 2 to 3 feet high (and 3 feet wide) in a nicely rounded shape with purple flowers that attract butterflies. Extended hardiness from Zones 3 to 8.
  • ‘Little Lady’ (S. x) is a compact lilac that matures to 4 to 5 feet tall and wide with dark pink buds that open to lilac-pink flowers. Hardy in Zones 2 to 7.
  • ‘New Age Lavender’ and ‘New Age White’ (S. vulgaris) are super-compact, growing from 4 to 5 feet tall and wide, and bred for mildew resistance. Their fragrant flowers attract butterflies and hummingbirds. Hardy to Zone 4.

See more lilac varieties!

Wit and Wisdom

  • To improve the flowering of lilacs, keep the grass from growing around them. A 16- to 24-inch circle of landscape cloth placed around the bushes and covered with bark or stone will keep the grass down.
  • Force a winter bouquet from cut branches of lilac. Bruise the cut ends and set them in water. Spray the branches frequently. Keep them in a cool place until they bloom, then move to a warmer area for display.
  • Poet Walt Whitman thought of lilacs when Abraham Lincoln died: 
    ”When lilacs last in the dooryard bloom’d … I mourn’d, and yet shall mourn with ever-returning spring.”
  • Lilacs supposedly symbolize the joy of youth. Learn about more flower symbolism here.
  • The lilac belongs to the olive family, Oleaceae.
  • Lilacs are the state flower of New Hampshire.

Shrubs and Trees

About The Author

Catherine Boeckmann

Catherine Boeckmann

Executive Digital Editor and Master Gardener

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana.

Read more from Catherine Boeckmann

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Comments

<span>Amy Gettinger</span> Mon, 06/10/2019 - 14:20
My lilac bush is tall and skinny. It looks super healthy and blooms beautifully but I don't know how to get it to bush out. All the lilacs I have ever seen get nice and round and full....Mine looks like a pole... what do I do?
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 06/12/2019 - 13:43

As you suggest, this is not usually a problem. So the solution provided by the Cornell U coop extension may seem like an odd answer but here goes: prune it. (Have you ever prune it?) Specifically, the coop ext says, You can prune overgrown lilacs (if relatively healthy) down to the base of the plant in late winter/early spring. This action will force new vigorous growth and put you back on the road to having a beautiful, properly proportioned shrub. Blooms may be sacrificed for two to three years while the shrub is reestablishing itself. Once rejuvenated, maintenance pruning should be performed on an annual basis.

This sounds severe, but promising, if you can wait for the regrowth. You might also consult the nursery you purchased it from (or any nursery) to see what they recommend.

 <span>Mary Walzer</span> Fri, 05/31/2019 - 19:22
Will lilac roots damage the leach lines from my septic tank? If so, how far from them do I have to plant the lilac to keep the roots away? Thank you
<a title="View user profile." href="/author/editors">The Editors</a> Wed, 06/12/2019 - 13:35

There are some general standards re distance; lilacs that 8 to 10 feet from water and sewer lines should be fine.

Lilac roots will probably not break intact pipes, but they could be drawn to pipes that leak.

For more information you could contact your town inspector or a nursery person.

 <span>Gail Donahue</span> Thu, 05/09/2019 - 15:44
can I plant a lilac bush close by morning glories or with the roots bother the lilac bush
<a title="View user profile." href="/author/editors">The Editors</a> Mon, 05/13/2019 - 16:18

Morning glory roots shouldn't be an issue for lilacs, since the lilac roots will reach much deeper than the morning glories. Plus, morning glories are annuals, meaning they die back at the end of the growing season and will no longer be a competitor to the lilac.

 <span>Shirley Rasmussen</span> Mon, 04/29/2019 - 14:31
I am putting a bed of rocks near a thriving lilac bush. I do not want the suckers to come up under, through the ground cover and into my bed of rocks. How deep would I have to bury a barrier? 6-8 inches deep enough? Or is there any way to keep the suckers controlled and in a confined area? If I cut suckers off each year, to keep in a confined area, will they continue to spread out farther?
<span>Jane W</span> Thu, 02/28/2019 - 11:37
Hopefully someone can share a little insight. I've planted several lilacs along my back fence. I was in a quandary as to what to do regarding the invasive ground cover sneaking under the fence from my neighbors yard. I have attempted to pull it out , but presume that it will return repeatedly. Consequently I chose to plant each of my five lilacs in a circular barrier made from half a large trash barrel. The barrels are approximately 22 in in diameter and fourteen to sixteen inches in height. The hope is to allow the lilacs roots to grow below the barrier and spread as the plant matures while keeping the invasive ground cover with more shallow roots separate. Hopefully I'm not confining the lilac roots if they tend to grow more shallowly themselves. Any thoughts out there?
<a title="View user profile." href="/author/editors">The Editors</a> Fri, 03/01/2019 - 15:24

Almost everything works for a while. You are removing the bottom from the barrels, right? If you do not, you will confine the lilac roots and eventually they will cease to thrive (we're guessing that would happen before the barrels break down to release the roots). And you're setting the barrels deep enough to have the rim at ground level? Or are the barrels going to be above ground, shielding 14 to 16 inches of lilac trunk? 

You do not name the ground cover but you are probably correct in expecting it to return, despite your pulling it out. (There is a saying about ground covers: the first year it sleeps, the second year it creeps, the third year it leaps.) If the barrels are aboveground (not sunk to the rim) the ground cover roots could eventually make their way past the barrel barrier. Could you sink edging between you and your neighbor? A healthy lilac will send out suckers, too. Whether these appear within the perimeter of your barriers or reach from the depths and "pop up" outside of the barrier remains to be seen.

Another thought is to mulch the lilacs. A thick (3 to 4 inch) layer should help to deter or slow down the ground cover.

Hope something here helps.

 <span>Lainey</span> Fri, 03/15/2019 - 08:03
The idea of sinking a barrier between yards is a great, I'm going to try this too!