Hardy Gardenia That I Saw In Zone 4

Question

I read your article saying that there are no Gardenia species that grow past zone 7 but I have seen Gardenia species grown in zone 4. When i went to school at Winona State University, Winona Minnesota, I have seen a gardenia plant that comes back year after year. The plant is located in front of the library in the garden in front of the library door on the north side of library. In the year 2009, we had a temperature up to negative 50 degrees Fahrenheit and very cold for a week. The flower bloomed very well during early May. I still see that Gardenia plant in pictures uploaded by University during spring. The Gardenia plant I mentioned blooms every year just before graduation which is end of April and beginning of May months. Unfortunately, I do not know the species of that Gardenia, which I would happily buy if I ever find out.

Answer 1

So, I did all of the research I could, including pulling pictures of the building itself. I could not see any Gardenias, but I did see some white Viburnum in some of the photos. Some species can smell similar, and are hardy to zone 4. For example, Viburnum carlesii could look pretty similar in passing, and it does smell nice.

Checking horticultural databases in your area, and in known places where gardenia has been noted, I couldn't not find any reference to this happening. They have been noted growing on the edge of zone 7, but going down to zone 4 wouldn't be possible.

If there is a horticultural group there, maybe you could ask them about it. You could take samples up to your local extension service, as well.

The bottom of this article explaining about your local extension service will contain a search form at the bottom, as well. This will help you to find the closest one to you.

https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm