Blooming may be retarded by too much nitrogen – such as lawn fertilizer. Will grow in less than full sun, but bloom is diminished and susceptible to mildew
A full sun position will ensure your plant thrives and remember to water moderately. Keep in mind when planting that Alba is thought of as hardy, so this plant will survive close to or on freezing temperatures. Ensure your soil is loamy and clay and has a ph of between 6.0 and 7.5 as Common lilac is a weakly acidic soil to weakly alkaline soil loving plant.Some varieties will self-sow.
The genus name Syringa is derived from syrinx meaning a hollow tube or pipe, and refers to the broad pith in the shoots in some species, easily hollowed out to make reed pipes and flutes in early history.
A pale purple colour is generally known as lilac after the flower.
(from Wikipedia)
1 bachmanslandscaping.com/12070012/Plant/1456/White_French_Lilac