Q.Gardenia in a pot
Is it acceptable to leave a new gardenia plant in the pot that it was received in?

Certified GKH Gardening Expert
These are usually sold as mature as they can get in these containers. It is best to re pot it, but it can survive for a short time in that container. Nurseries usually maintain root, and top growth while they are in those containers, but this is not advised if you are new to these. Incorrect root pruning will kill it.
This article will give you more information on the plant: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-plant.htm