I bought the shrubs from a local grower and didn't write down the specific information you might need in order to find them.
The website New Plants and Flowers sent out the information we need for any future purchases. Here's a link to the nursery, J. Berry.
Gardenia jasminoides ‘Celestial Star’ is a 2016 introduction of J. Berry Nursery in Grand Saline, Texas (US). It is bred by Jim Berry who founded the company in 2006 together with Jonathan Berry. The scent of ‘Celestial Star’ is ‘remarkable’. The two describe the new Gardenia as a shrub that has striking double flowers. Heavy bloom set in spring with a follow-up show in the fall. No pruning should be required in the production period. Is has a fast growth rate and intermediate height; 4’ tall by 4’ wide. Zones 7 to 9.
J. Berry Nursery supplies ‘Celestial Star’ PPAF as liners and in 1- and 3-gallon containers.