Flowering in the mid- to late spring garden with massive displays of large, sweetly fragrant flowers, lilacs are admired throughout the landscape and beloved as a cut flower as well.
The large, pyramid-like panicles are dazzling in fabulous shades of magenta, mauve, purple, white, and yellow, broadcasting their rich perfume in wide, mesmerizing swaths.
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Tough, reliable, and easily cultivated, these multistemmed deciduous shrubs or small trees are orderly in growth habit and highly versatile in the landscape.
They’re also long-lived and can grow for over 100 years.
With early, mid-, and late season selections, it’s possible to plant for an extended season that lasts several weeks. And there are even reblooming varieties that flower all summer!
Common lilacs (Syringa vulgaris) are winter hardy, and typically require a cold winter in USDA Zones 3 to 7 to set flower buds – but there are other species and several newer hybrids which can thrive in the warmer climates of Zones 8 and 9 as well.
The sweet blooms are also highly attractive to important pollinators like bees, butterflies, and hummingbirds, but deer leave mature plants alone.
If your garden needs some trouble-free, fragrant flowering shrubs, join us now for a look at how to grow and care for lilacs.
Here’s what’s coming up:
What You’ll Learn
What Is a Lilac?
Syringa is a genus of flowering shrubs in the olive family Oleaceae, with around 25 species and hundreds of cultivars.
The common lilac, aka English or French lilac, S. vulgaris, is a species native to the rocky slopes and hills of the Balkan Peninsula in eastern Europe, while most other species are native to temperate regions of southeast Asia.
Widely cultivated for its beautiful, perfumed flowers in the spring garden, these deciduous shrubs or small trees generally reach mature heights of three to 20 feet, depending on the cultivar.
However, the Japanese tree lilac (S. reticulata), among the largest species, can grow as tall as 40 feet. You can read all about it in our guide to growing and caring for Japanese tree lilacs.
Plants colonize readily and each year produce several secondary shoots, or suckers, around the base which can eventually form a small thicket if not selectively pruned out.
The large single or double flower panicles bloom in shades of magenta, mauve, purple, rosy-mauve, and white, and there are a few lemon yellow cultivars as well.
Lilacs flower in spring, and there are early, midseason, and late season selections as well as recently introduced reblooming varieties that flower intermittently throughout summer.
The simple leaves are heart-shaped or oval in shades of light to glaucous green.
Most cultivars of S. vulgaris do best in regions with cold winters.
A period of about 42 cool days with temperatures below 50°F is required for bud set, according to “Lilacs: Beautiful Varieties for Home and Garden” by Naomi Slade.
This book is available on Amazon.
But there are also several selections suitable for areas with mild winters, such as S. x oblata ‘Betsy Ross,’ S. patula ‘Miss Kim,’ and the cutleaf lilac, S. laciniata.
Other popular, decorative selections for the home gardener include varieties such as Chinese (S. × chinensis), dwarf Korean (S. meyeri), early hybrid (S. x hyacinthiflora), Persian (S. × persica), and Preston lilacs (S. x prestoniae).
Cultivation and History
The genus name Syringa comes from a Greek word for tube or pipe, syrinx, thought to reference their pithy but easily hollowed stems.
According to Greek myth, the river nymph Syrinx escaped the attentions of the lusty satyr Pan by turning herself into a bush of hollow reeds (lilac), from which he made his first set of panpipes.
The word lilac comes to us from an old French variation of the Persian lilak or nylac, meaning blue or bluish.
By the 15th century, lilacs had spread west along trade routes through Europe and came to North America with the early colonists. Both George Washington and Thomas Jefferson were known to grow them in their gardens.
Lilac Bush Propagation
The easiest ways to propagate lilacs are to transplant suckers from a parent plant, or to root stem cuttings.
The season before transplanting, check that the suckers’ leaves are the same as those on the parent plant.
If they’re not, the parent scion is grafted to rootstock of another variety, and propagated suckers will not be true to the parent.
This is sometimes true of tree form plants, and it was once common to graft lilac with privet rootstock.
You can also propagate lilacs by sowing seed or air layering.
Transplant suckers in late winter or early spring when the plants are still dormant.
Choose healthy, strong suckers at least one year old, with their own roots, and growing a minimum of 24 inches away from the parent shrub.
The further away they are, the less chance there is of damaging the parent when you dig.
Create a planting hole eight inches deep with a 16- to 24-inch diameter.
Amend the soil with a couple shovelfuls of organic matter such as compost and mix well. Stir in a bit of bone meal to aid with healthy root growth.
To lift suckers, use a clean, sharp spade and push straight down about eight to 10 inches out from the stem.
Circle the stem with several cuts, severing the stolon (or runner) where it attaches to the parent plant as you go.
Slide the spade under the root ball and pry gently to lift it out.
Set your sucker inside the prepared hole, carefully spreading the roots on the bottom and setting the crown at the same depth as in its original location.
Backfill with soil and firm in place. Water gently but deeply.
From Softwood Cuttings
Cuttings are a bit less reliable, but propagating new plants with these is still doable. Plan to cut a few more than you’ll need to improve your chances of success.
It’s best to take cuttings in early summer after flowering, and you should avoid using old wood for propagation. Instead, choose new growth that has ripened for at least a month, flexible stems that are about as thick as a pencil.
Take cuttings in the morning when temperatures are cooler and plants are well-hydrated.
Use clean, sharp garden shears to cut four- to six-inch stems just below a leaf node.
Remove the bottom leaves but leave the top cluster in place. To help with rooting, dip the stripped portion of the stem in rooting hormone powder. Shake gently to remove the excess.
Fill a six-inch pot with a starter soil mix and water until it’s moist but not wet.
Insert two or three stems per pot, covering all nodes where leaves have been removed, spacing them evenly and firming them in place.
Place in a warm, bright location out of direct sun, such as on top of a heat mat near a window. Cover with a perforated clear plastic bag to retain humidity. Keep the soil moist but not wet.
Cuttings should root in four to eight weeks, which is indicated with the appearance of new growth.
Once rooted, move pots outdoors to a protected location with bright, indirect light and allow the top inch of soil to dry out between waterings.
Provide rooted stem cuttings with protection against freezing temperatures for their first winter, then plant out the following spring.
The most time-consuming method, it will be quite a while before you see blooms on lilacs started from seed. But this can be a fun way for avid growers to develop their own unique varieties.
Immediately after collection from mature plants, sow the fresh seed into small containers with drainage holes, filled with seed-starting mix. Cover lightly, and water well.
Containers can be placed outside in a protected area to cold stratify the seeds. Keep the soil moist, and be on the lookout for seedlings to sprout in the spring.
Via Air Layering
Branches growing near the ground are perfect for starting new plants – but again, this is not the best option if you wish to see quick results, and rooting can take months or even years.
Bend a healthy, pliable branch to the soil and pin it down with a rock, wire, or floral clips. Continue caring for the mature plant as you normally would, and roots will develop where the branch has made contact with the soil.
To speed this process, some growers will wound the branch by scraping the outer bark where it will make contact with the soil, and then dip it in a powdered rooting hormone. Loosening the soil or slightly burying branches that you wish to root can also help to speed things up.
When strong roots develop, clip away the branch, dig it up, and transplant.
How to Grow Lilac Flowers
Lilacs are best planted in the fall before freezing temperatures arrive, or in early spring after the soil thaws.
They thrive in a full sun location in humus-rich, well-draining, slightly alkaline soil with a pH of 7.0 to 8.0. They can tolerate a little shade but too much results in fewer blooms.
Prepare the planting site by digging a hole the same depth of the root ball and twice as wide.
To enrich the soil, mix in generous amounts of well-rotted compost or aged manure. Add a small handful of bone meal for healthy root growth.
Set the plant in the hole with the crown positioned about an inch above the soil line. Backfill with enriched soil and firm in place.
Most lilacs sold today are not grafted, and this is more common with tree forms. Some gardeners recommend planting grafted specimens with the graft point below the soil to encourage the scion of your selected cultivar to develop roots.
Bare root specimens should be soaked in water for an hour before planting, spreading the roots out in the hole over a small mound of soil before backfilling.
Water deeply, providing one to two inches of water per week throughout the growing season for the first two years in the absence of rain. Mulch can be used around the root zone to retain moisture.
From the third year onwards, water during bud set and flowering, and only when you go without rain for a month or longer otherwise.
For container growth, choose compact or dwarf varieties. Learn more about care and cultivation in our guide to growing lilacs in pots and planters.
Lilacs are generally low-maintenance, but the following tips can help ensure healthy, floriferous growth:
- Plant in full sun – six to eight hours daily – for the showiest displays.
- Ensure the planting site is well-draining as Syringa doesn’t do well in soggy conditions.
- Each year, allow a few suckers to remain and grow, eventually cycling out old or overgrown stems.
- In areas with mild winters, help plants enter a state of dormancy by withholding water starting in late September. Resume watering again in February.
Along with these growing tips, a little annual maintenance can help to keep them at their best.
Pruning and Maintenance
For their first two years in the garden, fertilize lilacs in early spring with a 5-10-10 NPK formula.
After that, the shrubs generally require only a two- to four-inch layer of organic mulch applied over the root zone in early spring.
In fall, some gardeners broadcast garden lime over the root zone. This helps to maintain a slightly alkaline pH and intensifies flower colors.
To direct more energy into bud formation for the following year, deadhead faded flowers as soon as they begin to droop and wilt. But don’t wait too long or you’ll be removing next year’s nascent buds.
For annual maintenance, prune to size or thin shrubs as needed to improve airflow by cutting back branches right after flowering, using clean, sharp garden shears.
Cut back at a 45-degree angle, cutting just above an outward facing leaf bud.
Also, remove most suckers when you see them by cutting just below the soil level.
As shrubs mature, it’s a good idea to select and allow a few of the strongest and healthiest suckers to continue growing – these will be used to replace old, underperforming stems when needed, and they will begin to produce flowers in two to three years.
Select suckers that are further away from the parent plant if you can, to avoid root disturbance when you transplant.
To rejuvenate shrubs that have become leggy or those with declining flower production, remove up to one-third of the lankiest stems by cutting right to the ground in early spring while they’re still dormant, selecting canes that are at least two inches in diameter.
Repeat each spring for the next two years.
Lilac Species, Hybrids, and Cultivars to Select
With hundreds of selections available, you’re sure to find the right lilac – or several – for your garden!
Here’s a sampling to get you started. And for more ideas, be sure to read our guide to 23 of the best lilac varieties.
Compact, floriferous, and highly fragrant, ‘Baby Kim’ (aka ‘SMNSDTP,’ which is much more difficult to pronounce) features beautiful, perfumed panicles of mauve flowers that retain their color without fading.
Blooming in late spring to early summer, ‘Baby Kim’ has tidy growth and is self-cleaning – which means it doesn’t require deadheading.
The dwarf plants reach a mature height of two to three feet with a similar spread.
Low maintenance with a trim shape, this hybrid cultivar makes an outstanding choice for containers, foundations, low hedges, patio planters, and lining entryways or walkways.
These shrubs are hardy in Zones 3 to 8, and are among the best for regions with mild winters.
Plants in quart- and gallon-size nursery containers are available at Home Depot.
A garden classic, common lilac (S. vulgaris) delights with masses of large and highly fragrant mauve flowers in the late spring garden.
The lush, attractive foliage turns yellow in fall for a second season of interest and plants reach a height of 10 to 15 feet with a spread of six to 10 feet.
A gorgeous choice where the perfume can be enjoyed in a hedge, privacy screen, or as a stand-alone specimen in butterfly, cottage, and cutting gardens, these plants are hardy in Zones 3 to 7.
This species is available for purchase at Planting Tree in several sizes.
Superbly fragrant with lavender-pink flowers, ‘Josee’ is a sensational dwarf shrub with a heavy load of rosy-mauve flowers in late spring. It reblooms intermittently until first frost.
The compact hybrid plants are low maintenance and reach a mature height and spread of four to six feet.
They also have excellent heat tolerance, and they’re well-suited for warmer winter climates.
A superb choice for barriers, containers, foundations, and low hedges, or in city and courtyard gardens.
This cultivar features moderate tolerance for pollution and the plants are hardy in Zones 3 to 9.
‘Josee’ is available at Nature Hills Nursery.
New Age White
A dwarf cultivar of the common lilac, ‘New Age White’ (S. vulgaris ‘G13103’) is part of the Bloomables® collection from Star Rose and Plants that adds masses of pure white, fragrant flowers to the late spring garden.
The compact plants are freely branching, disease resistant, and grow to a height and width of four to five feet. They’re hardy in Zones 4 to 8.
Ideal for small spaces, ‘New Age White’ is perfect for containers, foundations, low hedges, patio planters, and placement in city or courtyard gardens.
This cultivar is also a good choice for regions with mild winters.
Find plants at Nature Hills Nursery.
True to its name, ‘Purple Glory’ is rambunctious, prolific, and impressive with big cones of dark, magenta-purple buds that open to fantastically fragrant, blue-mauve flowers.
These early-flowering S. x hyacinthiflora shrubs are in full bloom two to three weeks before the common S. vulgaris varieties begin to flower.
Plants maintain a smaller size, with a mature height of six to eight feet and spread of five to six feet, and the deep green foliage turns handsome shades of burgundy in fall.
Hardy in Zones 3 to 8, they make a superb hedge, privacy screen, or specimen, and provide excellent cut flowers as well.
Plants are available at Nature Hills Nursery.
Managing Pests and Disease
Lilacs are known for being trouble-free, but a few pests or pathogens may occasionally come to call.
Rabbits, mice, and voles may appreciate a nibble. Consider fencing if these pests are a common problem in your garden.
Be on the lookout for leaf mining moths, lilac borers, and thrips.
Tiny scale insects may also attack lilacs, and these insects are often confused for cotton-like or waxy growths on branches, leaves, and stems.
If groups of scale are clustered in a single location, prune and destroy the branch where they’re located. Otherwise, spray with neem oil and repeat as needed until plants are problem-free.
These plants may occasionally suffer from blight or armillaria. But the most common disease issue for lilacs is powdery mildew, which is caused by fungal pathogens in high humidity.
The best prevention method is to choose resistant varieties.
Improving air circulation is the best treatment for infected plants. Thin mature plants annually if powdery mildew is a recurring problem in your area.
Best Uses for Lilac Shrubs
Lilacs are outstanding as stand-alone specimens anywhere their color and fragrance can be enjoyed.
Plant beside entryways, in foundation plantings, around patios, and under windows to enjoy their scent indoors as well.
Large shrubs also make attractive hedges and privacy screens. And compact or dwarf varieties are excellent for containers and planters or in smaller city and courtyard gardens.
They also make a sweetly scented cut flower and are a staple in cutting gardens.
Quick Reference Growing Guide
|Plant Type:||Woody shrub, small tree||Flower/Foliage Color:||Magenta, mauve, purple, white, yellow/medium to deep green|
|Native to:||Eastern Europe and southeast Asia||Maintenance:||Low|
|Hardiness (USDA Zones):||3-7 (8 and 9 for some varieties)||Tolerance:||Deer|
|Bloom Time/Season:||Early, mid, and late spring||Soil Type:||Humus-rich|
|Exposure:||Full sun||Soil pH:||7.0-8.0|
|Time to Maturity:||2-3 years to bloom||Soil Drainage:||Well-draining|
|Spacing:||2-6 feet, depending on variety||Attracts:||Bees, birds, butterflies, hummingbirds|
|Planting Depth:||Crown at soil level (transplants)||Uses:||Containers, hedges, privacy screens, specimens, patio planters; city, courtyard, and cutting gardens|
|Height:||3-20 feet, up to 40 feet for tree forms||Order:||Lamiales|
|Common Pests and Diseases:||Leaf miners, lilac borers, scale, thrips; armillaria, lilac blight, powdery mildew||Species:||Chinensis, hyacinthiflora, meyeri, oblata, patula, persica, prestoniae, vulgaris, and hybrids|
A longtime garden favorite, lilacs are beloved for their gorgeous, sweetly perfumed flowers.
Low maintenance and easy to cultivate, they’ll flower for decades with little effort on the gardener’s part.
And you won’t be able to resist bringing these heady blooms indoors for cut arrangements!
Remember to deadhead promptly after flowering for plenty of flowers next year and encourage a few healthy shoots to grow for cycling out the old with healthy new stems.
Do you folks have favorite lilac varieties? Let us know in the comments section below.
And for more info on flowering shrubs, add these guides to your reading list next: