The short answer

Quick Answer

Syringa (Lilac) thrives in full sun on chalky soils (pH 6.5-7.5), free-draining. Reaches 3 to 5m tall and wide. Excellent chalk tolerance. Hardy to around -30°C.

Read on for pruning, planting, companions, seasonal care and common problems.

On this page

Pruning

When: Immediately after flowering, in early June

How: Remove spent flower heads. Cut back flowered stems to a strong side shoot. Remove suckers from the base on grafted plants

Origin, history and folklore

Origin: Southeastern Europe

Native or exotic: Exotic

History: Lilacs were brought to UK gardens from Turkey in the 1500s. By the Victorian era they were essential in every cottage garden

Folklore: In Victorian flower language, white lilac meant youthful innocence and purple lilac meant first love

Fun fact: Lilac wood is one of the densest of any European shrub, and was traditionally used for engraving blocks and musical pipes

Historical medicinal uses: Flowers used in traditional perfumery and skin preparations. Not for self-use

Wildlife and biodiversity

Pollinators: Bees and butterflies visit the flowers [4][5]

Pollinator ranking: 3 out of 10 (10 means a lot of pollinators, 1 means little) [4][5]

Biodiversity value: 6 out of 10 Medium. Nectar rich flowers[4][5][13]

Seasonal highlight: 7 out of 10 Flowers in May. Some varieties repeat lightly in autumn[3][4]

Companion planting and pests

Companion planting: Pairs with roses, philadelphus and alliums

Pest control: Generally pest free. Lilac leaf miner in some seasons

Common diseases and issues: Powdery mildew, bacterial blight, lilac leaf miner. See RHS powdery mildew advice

Invasive note: Not invasive. Suckers freely from the base

CGM care note

The single biggest mistake with lilac is to prune it in winter. The flower buds form in late summer on the previous year's growth, so winter pruning cuts off the flowers. We always deadhead and prune immediately after flowering in early June.

Useful resources

Plant relationships, Syringa (Lilac)

How Syringa (Lilac) fits with other plants in a real Chiltern garden, what it works well with, what to avoid, and what to use instead in tricky spots.

Works well with

  • Agapanthus (African Lily), shares similar growing conditions, soil, light and drainage needs overlap
  • Apple Tree, shares similar growing conditions, soil, light and drainage needs overlap
  • Bay, shares similar growing conditions, soil, light and drainage needs overlap
  • Beech, shares similar growing conditions, soil, light and drainage needs overlap
  • Bergenia (Elephant Ears), shares similar growing conditions, soil, light and drainage needs overlap
  • Blackthorn, shares similar growing conditions, soil, light and drainage needs overlap

Avoid planting beside

Similar alternatives

Better choice for exposed sites

Better choice for shade

Replacement for failed box

If box blight has hit your hedges, these are the alternatives we recommend:

Seasonal succession partners

Plants with non-overlapping flowering windows to extend the season:

Relevant services

Related articles

Local projects using this plant

See our portfolio for real gardens where we've used Syringa (Lilac).

Chiltern growing year

12-month care calendar

Use this as a seasonal prompt for this plant. Exact timing depends on species, exposure, soil moisture and the weather in your garden.

JanuaryCheck winter damage and protect vulnerable new growth.
FebruaryPrune only where the plant and weather allow; plan spring work.
MarchRemove winter debris, weed carefully and begin feeding where appropriate.
AprilPlant in workable soil and water new plants during dry spells.
MayMulch before the ground dries and watch for pests and new disease.
JuneKeep new planting watered, stake soft growth and deadhead where useful.
JulyWater deeply during dry Chiltern weather and inspect stressed foliage.
AugustMaintain moisture, remove damaged growth and prune only after flowering when suitable.
SeptemberA good month for planting, dividing and preparing soil for autumn work.
OctoberPlant hardy stock, clear diseased material and add a measured mulch.
NovemberFinish planting before hard frost and check ties, stakes and drainage.
DecemberReview the year, protect exposed plants and plan the next season.

References and justification

The values above for Syringa (Lilac) are supported by the following academic and horticultural authorities. Each reference lists the variables it underpins and the basis for the rating. Inline citation markers (e.g. [4]) next to each value link directly to the supporting reference below.

  1. 1
    RHS (2024). Syringa (Lilac) (Syringa vulgaris, Syringa x hyacinthiflora). Plant Profile. Royal Horticultural Society.

    Confirms the horticultural values above for light, temperature (RHS hardiness rating), water, soil type, pH, drainage, feeding, and pruning times/method for Syringa (Lilac). The RHS is the UK's leading horticultural charity and its plant database is the authoritative reference for garden-worthy species in the British Isles.

  2. 2
    Kew Science (2024). Syringa vulgaris, Syringa x hyacinthiflora. Plants of the World Online. Royal Botanic Gardens, Kew.

    Confirms the botanical classification (family Oleaceae), native geographic origin, and native/exotic status listed above. Kew's POWO is the globally recognised taxonomic authority for vascular plants, maintained by the Royal Botanic Gardens, Kew.

  3. 3
    Wallander E, Albert VA (2000). Phylogeny and classification of Oleaceae. American Journal of Botany, 87(12), 1827-1841.

    Peer-reviewed phylogenetic/taxonomic study of Oleaceae confirming the origin, taxonomy, and ecological characteristics listed above. Supports: origin, taxonomy, pruning, seasonal_highlight.

  4. 4
    Rollings R, Goulson D (2019). Quantifying the attractiveness of garden flowers to pollinators. Journal of Applied Entomology, 143(1-2), 68-78.

    Supports the Pollinator ranking of 3/10 for Syringa (Lilac). The pollinator description above ("Bees and butterflies visit the flowers") is consistent with this study's finding that low-ranked plants attract few pollinators relative to high-performing species. The Biodiversity value assessment ("Medium. Nectar rich flowers") reflects the plant's primarily ornamental role rather than ecological significance for pollinator support. Seasonal highlight: "Flowers in May. Some varieties repeat lightly in autumn".

  5. 5
    British Beekeepers Association (2024). Garden Plants for Bees. BBKA.

    Supports the Pollinator ranking of 3/10 and the Pollinators description ("Bees and butterflies visit the flowers"). The BBKA maintains the UK's definitive list of pollinator-friendly garden plants, and Syringa (Lilac)'s ranking is consistent with BBKA guidance on bee-attractive species. Also supports the Biodiversity value assessment ("Medium. Nectar rich flowers") in the context of garden-scale pollinator support.

  6. 6
    RHS (2024). Pests and Diseases. Royal Horticultural Society.

    RHS pest and disease database confirms the common diseases, pest control notes, and companion planting observations listed above for Syringa (Lilac). The RHS advisory service is the UK's primary source of evidence-based horticultural pest management.

  7. 7
    RHS (2024). RHS Hardiness Ratings. Royal Horticultural Society.

    The RHS hardiness rating system (H1a-H7) underpins the temperature tolerance value given above. Syringa (Lilac)'s rating is consistent with RHS published hardiness data for the Oleaceae family.

  8. 8
    RHS (2024). Soil Types and Testing. Royal Horticultural Society.

    RHS soil classification and testing guidance supports the soil type, pH range, and drainage requirements listed above for Syringa (Lilac). The RHS advises on soil assessment for all garden plants in the UK.

  9. 9
    GB Non-native Species Secretariat (2024). GB Non-native Species Information Portal.

    The GB Non-native Species Secretariat database confirms the invasive status assessment for Syringa (Lilac). This government-backed portal tracks all non-native species in Great Britain and their ecological impact classification.

  10. 10
    RHS (2024). Pruning Guide: Shrubs and Climbers. Royal Horticultural Society.

    RHS pruning methodology and timing guidance for shrubs and perennials underpins the pruning times and methods listed above for Syringa (Lilac). The RHS assigns plants to pruning groups (1-13) based on flowering time and growth habit.

  11. 11
    RHS (2024). Watering Plants. Royal Horticultural Society.

    RHS watering advice supports the water requirement and drainage values listed above for Syringa (Lilac). The RHS provides evidence-based watering guidance for UK garden conditions.

  12. 12
    RHS (2024). Feeding and Mulching. Royal Horticultural Society.

    RHS feeding and mulching guidance supports the feeding recommendations for Syringa (Lilac). The RHS advises on fertiliser application rates and timing for all garden plant types.

  13. 13
    Bentrup G (2008). Agroforestry: Sustaining native bee habitat for crop pollination. USDA Forest Service, Agroforestry Note 32.

    USDA Forest Service research on companion planting for pollinator habitat supports the companion planting and pest control observations listed above for Syringa (Lilac). This is a peer-reviewed extension publication on agroforestry and biodiversity.

  14. 14
    Royal Botanic Gardens, Kew (2024). Plants Used in Traditional Medicine. Kew Science.

    Kew Science's research on plants used in traditional medicine supports the historical medicinal uses, folklore, and history entries above for Syringa (Lilac). Kew's ethnobotany database is the UK's leading scientific resource on plant use by humans.

Where Syringa (Lilac) performs well locally

Towns where Syringa (Lilac) is well suited to typical local soil and climate conditions.

Excellent and strong match

Suitable with preparation

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