Common Lilac in April: monthly care

Common lilac thrives in full sun or partial shade, though flowering is most abundant in a sunny position. It tolerates a wide range of soils—loam, chalky, and clay—but prefers neutral to slightly alkaline conditions with good drainage. Avoid waterlogged sites, as lilacs dislike sitting in wet soil. Plant bare-root lilacs in October, November, March, or April, when the ground is workable and not frozen. Container-grown specimens can go in at any time during these months, though autumn planting gives roots time to establish before spring growth. Dig a hole roughly twice the width of the root ball and deep enough so the top of the root ball sits level with the surrounding soil. Break up compacted soil at the base of the hole and incorporate a handful of garden compost or well-rotted manure to improve structure, especially in heavy clay. Space plants 250 cm apart to allow for their mature spread of 200–400 cm. If planting a hedge or screen, maintain this spacing to ensure good air circulation and reduce the risk of powdery mildew. Position the plant so the graft union (if present) is just above soil level. Backfill with the excavated soil, firming gently with your heel to eliminate air pockets. Water thoroughly after planting to settle the roots, then apply a 5–7 cm layer of organic mulch around the base, keeping it clear of the stems. Stake only if the site is very exposed or the plant is top-heavy; lilacs develop sturdy root systems quickly and rarely need long-term support.

Common lilac has low water needs once established. Water newly planted shrubs regularly through their first growing season—weekly in dry spells—to help roots settle in. After that, lilacs are remarkably drought-tolerant and usually need watering only during prolonged summer droughts. Overwatering or poorly drained soil can lead to root rot, so err on the dry side. Feed once a year in March with a balanced general-purpose fertiliser (such as blood, fish and bone or Growmore) scattered around the base at the rate recommended on the packet. Alternatively, apply a 5 cm layer of well-rotted compost or manure as a mulch in early spring; this feeds the soil and suppresses weeds. Avoid high-nitrogen feeds, which promote leafy growth at the expense of flowers. Lilacs growing in chalky or alkaline soils rarely need additional feeding. Renew mulch annually in spring, keeping it a few centimetres clear of the stems to prevent collar rot. In autumn, rake up and bin fallen leaves if powdery mildew has been a problem; this reduces overwintering spores. Common lilac is fully hardy across temperate Europe and needs no winter protection. Pests are few: lilac leaf miner can cause brown blotches on foliage in summer, but damage is cosmetic and rarely serious. Powdery mildew may appear as a white coating on leaves in dry summers, especially on plants in shade or crowded positions; improve air flow by thinning congested growth and avoid overhead watering. Lilac blight (bacterial disease) causes blackened shoots; prune out affected growth promptly and disinfect tools afterwards.