Ask Mr. Smarty Plants

Philadelphus x lemonei 'Innocence', is a hybrid (the "x" in the middle) and not native to North America. From ArcaMax, here is a website on it that may answer your questions. The Lady Bird Johnson Wildflower Center, home of Mr. Smarty Plants, is dedicated to the growth, propagation and protection of plants native not only to North America but to the area in which they grow naturally.

There are 8 members of the genus Philadelphus (mock orange) native to Texas, but only one, Philadelphus pubescens (Hoary mock orange) is native to your area of northeast Texas, on the state line with Oklahoma. It is native to Red River County, right next to Lamar County, so you probably have compatible soils. The problem there is that whatever this plant was hybridized with (lemonei) may have changed the acceptable growing conditions. We know it is related to hydrangeas and prefers acidic soils, which you have in East Texas. Follow the plant link above to find out about the normal growing conditions and try to work out a plan for growing your non-native from that.