Can balsam poplar trees grow in zone 7a?
Can balsam poplar trees grow in Oklahoma, specifically, Shawnee, Oklahoma?
Zone 7 temperature-wise it should be okay, as long as you can give it good growing conditions and plenty of water.
Hardy in USDA Hardiness Zones 3-9.
But I don't have personal experience with balsam poplar in Oklahoma, so check with a local nursery, landscape professional or arborist, or university ag extension service.