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Growing lilacs for Minnesota landscapes

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Quick facts 

  • Lilacs may take a few years to bloom after planting. 
  • Once established, lilacs can live a long time.
  • Lilacs need pruning immediately after blooming to promote flowering the next year.
  • Lilacs usually produce new growth (suckers) from the root area.
  • Planting a variety of lilac species and hybrids can provide continuous fragrance and extend the bloom time into early summer.
Pink flowers of the lilac species S. vulgaris 'Mme F Morel'
S. vulgaris 'Mme F Morel'

Lilacs are a favorite, long-lived, spring-blooming shrub. They are primarily grown for their fragrant flowers ranging from white to pink to deep purple.

Lilacs are native to Eastern Europe and Asia. The genus Syringa comes from the Greek word syrinx meaning pipe or tube and refers to the lilac’s stem which can be hollowed out.

In the landscape, lilacs make excellent hedges, foundation plants, specimen plants, large borders and group plantings. Depending on the weather, they bloom for 10 to 14 days and have a distinctive sweet fragrance. 

Lilacs also provide habitat for small birds and pollinating insects.

Large lilac bush with purple flowers.
Lilac hedge and flowers of S. x hyacinthiflora 'Pocahontas'

Growing lilacs 

  • Hardiness zone: 3 to 7 depending on the species.
  • Full sun (6+ hours); less sun reduces flowering and increases powdery mildew.
  • Moist, well-drained soil; avoid wet soils with poor drainage.
  • Soil pH 7.0 to slightly alkaline. Have your soil tested by the U of M Soil Testing Lab.
  • Space new plants based on mature size. 
    • Planted too close, lilacs will require more pruning and will reduce bloom. 
    • Proper spacing increases air circulation and reduces powdery mildew. 
  • Once the lilac is established (2 to 3 years after planting), fertilize every few years with an all-purpose shrub fertilizer. 
    • Avoid applying lawn fertilizers near or around lilacs as the high nitrogen content will increase leaf production and decrease flower production.
  • Water after planting. Make sure the soil drains easily and does not pool. 
    • Poor drainage can result in stunted growth, fewer flowers and root rot.
  • This video (28:44) gives selection, planting and growing information.
Pruned lilac plant with white flowers and green leaves.
Pruned lilac plant, S. vulgaris 'Betsy Ross'

Pruning

Like other spring-blooming shrubs, lilacs develop flower buds for the next year after blooming during the current year. Lilacs should be deadheaded immediately after blooming to encourage good bud development and flowering the following spring. 

  • Deadhead: Use a hand pruner to cut off dead flower heads down to a pair of leaves, or use a hedge trimmer for larger plantings. Shear lightly, taking off only the dead flower heads.
  • Renewal pruning: Renewal pruning allows more light throughout an older plant and encourages new stems to grow and flower. Newly planted lilacs usually do not need pruning for 2 to 3 years and it will take 1 or 2 years before a lilac blooms. Years later, lilac stems can grow very large and tree-like and they will tend to shade out new growth at the plant base.
    • Use a lopper or hand saw to remove a third of the thickest stems at the base. 
    • Do this every year until all large stems are removed. 
  • Rejuvenation pruning is a technique for smaller, densely-branched lilacs like Korean or Meyer lilacs (Syringa meyeri) that have become overgrown. 
    • In late winter, use a saw or hedge trimmer to cut the entire plant to the ground. 
    • New growth will grow from the root area in spring. 
    • The plant may not bloom or sparsely bloom for 1 or 2 years.
White growth on lilac leaves from powdery mildew
Powdery mildew on lilac leaves

Common problems

Causes for a lack of flowers:

  • Plant is not yet well-established. After planting, a lilac’s energy reserves will be used to develop a strong root system rather than flowers or leaves. Some blooming may begin in years 2 and 3. Be patient and continue to care for your lilac.
  • Plants are not receiving enough sunlight. Make sure your lilac has 6 or more hours of full sun per day. If the lilac has become shaded by another plant over time, consider pruning the other plant.
  • Too much nitrogen fertilizer is being applied, causing the plant to put energy into growing leaves, not flowers. Don't apply lawn fertilizers (high in nitrogen) around the base of lilacs. Plant lilacs in garden beds, not lawns.
  • Pruned at the wrong time of year and cut off flower buds. Lilacs set flower buds for the next year right after blooming is finished, so prune immediately after flowering.
  • For more about lilac issues and solutions see What’s wrong with my plant?

Species and cultivated varieties of lilacs for Minnesota

The following section is not a complete list of cultivars available commercially. For a wider selection:

  • Visit your local garden center. Have a list of plant features you want in a lilac, especially the size of your planting space.
  • Use Plant Elements of Design. It is free and takes just a few minutes to set up and confirm your user account.
  • Read Lilacs for Cold Climates by Laura Jull, associate professor in horticulture, University of Wisconsin Extension. 

The following lilac species and cultivated varieties are organized by bloom time (early to late). Plant sizes are listed as height x width. Hardy in zones 3-7 unless otherwise indicated.

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Author: Julie Weisenhorn, Extension horticulture educator

Reviewed in 2024

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