Why does Lagerstroemia indica bloom with white flowers?

Lagerstroemia indica has varieties with white flowers, and the colors are rose red, scarlet, dark pink, reddish or purple white.

Lagerstroemia speciosa is a deciduous shrub or small tree of Lagerstroemia, and its height can reach 7 meters. Bark is smooth, gray or grayish brown; Twisted branches, slender branchlets, alternate or sometimes opposite leaves, papery, oval, oblong or obovate, green to yellow when young, purple-black when mature or dry, and ventricular dehiscence; Seeds have wings. The flowering period is from June to September, and the fruiting period is from September to June.