ABSTRACT
The common lilac (Syringa vulgaris L.) is a small deciduous tree with opposite, ovate leaves and fragrant flowers borne in panicles. The actual date upon which flower formation commences varies with cultivar. During the period of inflorescence formation in the summer, the outgrowth of buds is inhibted by the presence of leaves, for they will sprout if the leaves are removed. Once the inflorescence has been formed and dormancy has been broken, early flower development can be forced in various ways. When forcing is begun as early as September, it is possible that the plants are not truly dormant but are in a state in which growth is possible only at high temperature. Then, as more time is spent at low temperature, so the temperature range over which renewed growth can occur is lowered. A number of chemicals are effective in breaking dormancy, of which ether, chloroform, and hydrogen cyanide have been used commercially on lilac.
