Posted: 19/09/2014 at 16:18
Jess.......is your Gardenia G. jasminoides syn. florida ( Cape Jasmine, Common Gardenia )......frost tender and therefore generally sold as a House Plant ?
They prefer a shady situation indoors with a humus rich but well draining compost erring on the acid side of neutral. If it is that type, you are lucky to have it survive overwinter in the garden
There has been a fairly recent introduction ( I believe) of a similar plant but supposedly hardy ( sorry I don't know the name offhand ) and which is being sold as a garden shrub. If that one, I'd refer back to the supplier of your plant for further info. I'd imagine it would probably need the same sort of conditions as above but would apparently tolerate colder conditions.
Hope this is of some help