Ask Mr. Smarty Plants

One of the first instructions we would like to give to gardeners is to make two trips to the nursery. The first one is to select plants you are interested in, write everything you can find on the label down and go home and search on the plant on the Internet. If it appears that plant will thrive without major intervention (such as building a greenhouse) then you can go back and buy it. If you are ordering from a catalog, you will at least not have to make 2 trips to the nursery; but you still need to turn away from the gorgeous pictures and glowing descriptions and research the plant objectively.

Gardenia is a genus of 143 species, native to Africa and southern Asia. In North America, it is considered a plant for the southeastern gardens of the United States. From the University of Rhode Island, here is a fact sheet on gardenias. The article mentions growing it in a pot in full sun (sunny window?) in the winter in colder areas or planting in a sheltered spot and wrapping it in the winter.

When we searched the Internet on "growing gardenias in Canada" we found this article from Top Tropicals on growing gardenias, that said their outside planting should only be in USDA Hardiness Zones 9 and 10. This Atlas of Canada Plant Hardiness Map indicates that your location in Bruce County, on the shores of Lake Huron, is approximately 3B.

Since these are not plants native to North America, which is the center of interest for the Lady Bird Johnson Wildflower Center, home of Mr. Smarty Plants, we really can't tell you what you should do with your (in-ground, we presume) plants. We do hope you plan ahead next time.