Good evening Christine,

Thank you for your question & my apologies for my late response. Growing Gardenias in a container outside in Michigan can be challenging due to the cold winter temperatures. Gardenias are hardy in zone 7, which is warmer than Michigan's zone, where temperatures can drop to ten below zero to twenty degrees below zero. Since Gardenias cannot survive these temperatures, they need to be brought indoors during the winter months.

If you still wish to grow Gardenias in a container outside, you would need to ensure that the container is large enough to accommodate the plant's growth and that it can be moved indoors during the winter. Please note that while Gardenias are not suitable for outdoor container gardening in Michigan, you can grow them indoors with the right care and conditions. Gardenias require bright light, mild temperatures and high humidity to bloom. I’ve included a few links that you may find useful:

https://depts.washington.edu/hortlib/pal/on-overwintering-container-potted-gardenias/

https://planttalk.colostate.edu/topics/houseplants/1345-gardenia/

https://www.canr.msu.edu/resources/container_gardening_in_a_sunny_area

Good luck & have a great day!