With their pale purple to mauve blooms in May, Chinese lilacs (Syringa x chinensis) are a cheerful, profusely blooming addition to the spring garden. They are a moderately tall shrubbing species, eventually reaching a height of 8 to 12 feet and a spread of 6 to 10 feet. Chinese lilacs, like most species in the lilac group, grow relatively quickly.
Chinese lilac is a cross between Persian lilac (Syringa x persica) and common lilac (Syringa vulgaris). While Chinese lilacs are winter hardy to U.S. Department of Agriculture plant hardiness zones 3 through 7, the parent plants Persian lilac and common lilac are winter hardy to USDA zones 4 through 7 and 3 through 7, respectively. Dark green lanceolate leaves are roughly 3 inches long, while flower panicles grow up to 6 inches long in a conical shape.
The lilac is a deciduous shrub, and so loses its leaves every fall and begins growing anew in the springtime. It has a medium growth rate, which means it is capable of growing between 12 and 24 inches every year. Chinese lilac, therefore, tolerates pruning quite well, and will regain a few feet of height the year following a pruning. Rather than pruning severely every several years, however, you should prune lilacs as soon as flowers are spent. Removing the flowers and shaping the tree will result in fuller flower growth the following year.
Chinese lilac is a relatively low-maintenance plant. It will grow in light shade as well as full sun, though it blooms much better if grown in a non-shaded location. As long as soils are consistently moist and well-drained, it will tolerate a range of soil types. Its preference, however, is for organically rich soil in the slightly acidic to slightly alkaline range. Lilacs also rely on good airflow for healthy development, so pruning should take into account not only flower removal and good form, but also open branches and good circulation of air.
Chinese lilac is most spectacular in mid-May, when fully in flower. You should grow it somewhere its purple blooms will be in display in spring, but keep in mind that when out of bloom it is not a very showy shrub. When grown in rows it makes a good border, hedge or screen for the property line, and it can be grown ornamentally in masses or on its own as a specimen.