Q.Gardenia not growing
My husband and I recently cleared out this area on our front lawn that used to contain philodendron plants, junipers, and a pine tree. After a long while, we put in our patio and we planted a few gardenias around the patio. We bought the gardenias at Wal-mart and it was still young. After transferring it into the earth, about a month later we started seeing it turning yellow-brown and now they’re mostly crisp and leaves are falling apart.

Before planting outdoors, make sure the temperature is above 50-55 degrees.
Here is a link to the planting guide from Michigan bulbs that instructs how to store your plants until they are ready for planting - refer to page 2, "what to do when your plants arrive".
http://cdn0.michiganbulb.com/downloads/MB_PG_S14.pdf
For more information on growing burning bush, please visit the following link:
https://www.gardeningknowhow.com/ornamental/shrubs/burning-bush/burning-bush-care.htm

If the stem is still alive, it will regrow. I would give it a few weeks to see if the stem and branches start to grow new leaves. If you do not see any growth in a few weeks, it is likely dead.
These articles will help you as well:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm