Common lilac (Syringa vulgaris) is a deciduous shrub or small tree grown for its heavily scented flower clusters in white, pink, lilac or deep purple in May. It needs full sun – in shade it flowers poorly or not at all – and well-drained, loamy soil that is neutral to slightly alkaline (pH 6.5–7.5). Plant in autumn or early spring and water well during the first summer; established shrubs tolerate drought. Like forsythia, lilac forms next year's flower buds on the current season's growth soon after flowering, so any pruning must be done immediately after the flowers fade. Snip off spent flower clusters so the plant does not waste energy on seed, and remove suckers from the base of grafted plants in summer. Old, leggy shrubs that flower only at the top can be renovated by cutting a third of the oldest stems to the ground each year for three years. Cut stems for the vase when about half the flowers are open.