Is it in a cultivated area? It looks like Philadelphus.

It's in a neglected bed of Lily of the Valley that has coneflowers, milkweed, goldenrod and probably other native plants that have snuck in or been planted very haphazardly. I plan to keep spraying the LOV with Round Up until it stops returning, and encourage all the natives to increase. I don't know if I should try to make it look organized or not. Time wise, I vote not. I'll keep adding shade tolerant natives and see what survives.

Thanks for helping. Maybe I need to leave it another year and see what it does.

Martha