Q.best time to plant a tulip poplar
When is the best time to plant a tulip poplar in northern Middle Tennessee?
You can plant it now (as long as all danger of frost is past), but be sure to care for it diligently if your summer looks like it's going to heat up early. You could also wait till fall but depending on how young your tree is/will be at that time, it may be harder for it to get well-established. Avoid planting during the hottest part of the summer at all costs.
This article may help you:
https://www.gardeningknowhow.com/ornamental/trees/tulip-tree/growing-tulip-trees.htm