Shrub
How to grow lilac
Syringa vulgaris
Lilac wants full sun and fertile, free-draining soil that is neutral to alkaline; it is one of the best flowering shrubs for chalk and sulks on acid ground. Plant bare-root from November to March or pot-grown from October to March, allowing 3 m for a common lilac. It flowers in May and June on shoots made the year before, so deadhead and do any pruning straight after flowering, and no later than the end of June.
- Hardiness
- Fully hardy
- Position
- Full sun
- Soil
- Fertile, free-draining, neutral to alkaline
- Ideal pH
- 6.5 to 7.5
- Water
- Low to moderate
- Feeding
- Moderate feeder
Sowing and planting lilac
WhenPlant Oct to Mar; flowers May to Jun; deadhead and prune after flowering
Starting off
Plant bare-root Nov to Mar or pot-grown Oct to Mar in a sunny spot on neutral to chalky soil. Buy plants on their own roots where possible, as grafted ones throw suckers of common privet or wild lilac. Propagate by softwood cuttings 10 cm long in Jun with bottom heat at 20°C, or by digging up rooted suckers from own-root plants in Mar; seed takes 5 to 7 years to bloom.
Spacing and planting
Common lilac reaches 4 to 6 m tall by 3 to 4 m wide in 15 years; dwarf S. meyeri 'Palibin' stays at 1.2 m by 1.5 m. Plant specimens 3 m apart and 2 m from walls, in a hole twice the rootball width with the graft union at soil level. Only 'Palibin' and the 'Bloomerang' types suit a 45 cm pot.
Varieties worth growing
- 'Madame Lemoine'
- Double pure white from cream buds, heavily scented; the standard white lilac for well over a century.
- 'Charles Joly'
- Double, deep purple-red flowers in late May on an upright bush; one of the darkest.
- 'Sensation'
- Single purple florets each edged in white, unlike any other lilac. Occasionally throws a plain shoot, which should be cut out.
- Syringa meyeri 'Palibin'
- Dwarf Korean lilac, a dense mound about 1.2 m high covered in lilac-pink scented flowers in late May and June; for small gardens and pots, and it does not sucker.
- Bloomerang Dark Purple
- Compact, about 1.5 m, flowering in May and again in bursts from midsummer to autumn on new growth. Trim lightly after the first flush.
Lilac month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Plant bare-root in mild spells. Renovate an overgrown lilac by cutting the framework to 60 to 90 cm.
- February
Plant bare-root or pot-grown stock in mild spells.
- March
Last bare-root planting. Feed and mulch. Lift rooted suckers from own-root plants to make new ones.
- April
Flower buds showing. Water plants put in over winter.
- May
Flowering. Cut a few stems for the house.
- June
Deadhead straight after flowering and remove weak or crossing stems. Softwood cuttings. No pruning after this month.
- July
Water in dry spells; next year's flower buds are forming. Pick off mined leaves.
- August
Nothing to do. Bloomerang types flower again.
- September
Nothing to do.
- October
Plant pot-grown stock. Lime now if a pH test shows acid soil.
- November
Plant bare-root. Remove suckers from grafted plants. Rake up mildewed leaves.
- December
Plant in mild spells.
Feeding lilac
A moderate feeder that flowers best on fertile, limy soil. One balanced feed in March with a mulch is enough; extra nitrogen gives leaf and suckers, not flower.
Moderate, a balanced feed; too much nitrogen gives leaf, not bloom.
Feeding plan
Planting
Dust bare roots, or use 5 g per litre of rootball for pot-grown plants so it touches the roots: 50 g for a 10 litre pot. Once only.
March
100 g/m² scattered under the canopy and watered in, then a 5 cm mulch of garden compost. A shrub 1.5 m across covers about 1.8 m², so 180 g. Do not repeat later in the year.
March, in place of the 4-4-4, for a leafy plant in sun that will not flower
20 g/m² under the canopy, about 35 g for a shrub 1.5 m across, watered in.
October, only if a pH test reads below 6
Garden Lime (calcium carbonate)
200 g/m² over the root area, well under the label figure of about 0.5 kg/m² for a typical bed. Retest the following autumn before adding more.
March, pots
2 to 4 g per litre of compost on the surface, watered in: 80 to 160 g for a 45 cm pot (about 40 litres).
Signs to watch
Masses of leaf and no flowers on a young plant
Excess nitrogen or heavy shade; grafted plants also take 3 to 4 years to settle
Stop feeding, give full sun and sulphate of potash in Mar
Pale leaves and poor growth on acid soil
Lilac wants lime
Garden lime at 200 g per square metre in autumn
Older leaves yellow between the veins in Jul
Magnesium short on light soil
Epsom salts drench
Pests, diseases and problems
Young shoots, leaves and flower buds blacken and wither in a cold, wet spring, as if frosted
Lilac blight, a bacterial disease
Cut affected shoots back to healthy wood in dry weather and bin them. Thin crowded stems to let air in and avoid heavy nitrogen, which makes soft growth.
Brown blister-like blotches on leaves from June, then leaves rolled up from the tip
Lilac leaf miner, the caterpillar of a small moth, which also attacks privet
Pick off and bin mined and rolled leaves on small plants. On a large bush it is unsightly but does little harm.
White powdery coating on the leaves in late summer
Powdery mildew on a dry-rooted plant
Water deeply in dry spells, mulch in spring and rake up fallen leaves in autumn. It arrives too late in the season to affect flowering.
Leaves dull and silvery with tiny black specks in a hot summer
Privet thrips, a sap-feeder that also lives on lilac
Hose the foliage in the evening during hot spells and keep the roots watered. Damage is cosmetic.
Branches die back, bark at the base lifts to show a white fungal sheet smelling of mushrooms
Honey fungus, to which lilac is susceptible
No cure. Dig the plant out with as much root as possible and replant with something resistant.
Pruning
Pruning and care
Flowers on last year's wood at the shoot tips, so deadhead straight after flowering in Jun by snapping the spent panicle off above the two new shoots beneath, and do no other pruning then except removing weak, crossing stems. Remove suckers from grafted plants at the base, tearing rather than cutting. Renovate an overgrown lilac in Jan to Feb by cutting the whole framework to 60 to 90 cm; it regrows str
Good to knowDeadhead after flowering; prune lightly. Remove suckers on grafted plants.
Growing lilac in pots
Common lilac is too big and too hungry for a pot. Dwarf 'Palibin' and the Bloomerang types do well in a 45 cm pot of loam-based compost in full sun; do not use ericaceous compost. Water regularly from April to September, especially in July when next year's buds form, deadhead after flowering and top-dress each March. Repot every three years, or plant out when the shrub stops growing well.
Lilac: common questions
Why is my lilac not flowering?
Pruning at the wrong time is the commonest reason: lilac sets next year's buds soon after flowering, so anything cut after June takes the flowers with it. Shade, too much nitrogen, acid soil, and youth are the others, as a new plant can take three or four years to settle.
When should I prune a lilac?
Straight after flowering, in June. Snap or cut off the dead flower heads just above the pair of new shoots below, and take out weak or crossing stems. Hard renovation of an old, overgrown bush is done in winter, ideally January, cutting to 60 to 90 cm, at the cost of a year or two of flower.
How do I stop a lilac from sending up suckers?
Pull or tear each sucker off where it joins the root, since cutting at ground level makes more of them. Suckers come from the rootstock on grafted plants and are worse after root damage or hard pruning. Buying a lilac grown on its own roots, or the dwarf 'Palibin', avoids the problem.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.