Gardenia brighamii

The only Gardenia native to Hawaii. Can grow to be a small tree about 15 ft. Single white fragrant flowers are small, the petals recurved. Dark evergreen foliage. Comes from areas about 1000' to 1700' in dry tropical forests.  Only 15 and 20 trees left in the wild. There are only two plants in the wild on Oʻahu and one on the Big Island. Luckily they can be grown from cuttings or air-layered and are gaining in popularity. I grow them here at low elevation (200') with no problem, but because they come from a higher elevation they should take to growing in cooler areas as well. My guess would be that they would only tolerate a light frost.

Hawaiian Gardenia, know as Nanu in Hawaii