How tall can Lagerstroemia indica grow without grafting?

7 meters. According to Damei Garden Network, the height of Lagerstroemia indica is between 3 meters and 5 meters, and it can grow to 7 meters at the highest. Lagerstroemia speciosa is an ornamental tree with claw-shaped petals. These flowers are panicles of six petals. They look very romantic and have rich colors, ranging from light red to deep red, and some colors are purple or white.