Answer: Most gardenias are hardy to zone 8. Your zip code places you in zone 7A which is significantly colder. Also, microclimate can be significant in that your location might be as cold as zone 6 if it is windy or exposed or otherwise subject to colder temperatures than the general area. So whether or not they will grow for you at all is going ot take some experimenting. Only the most winter hardy varieties would possibly survive the cold in your area. Your local professional nursery staff and/or county extension should be able to help you analyze the growing conditions in the site where you are thinking of putting a gardenia and make sure it is suitable. Since you are in zone 7A, you need to look only at the hardier types of gardenia such as "Chuck Hayes" and "Kleim's Hardy". I'm sorry I can't be more encouraging.
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