Gardenia plant named 'RLH-GA1'

A new and distinct cultivar of Gardenia plant named 'RLH-GA1', characterized by its compact, upright to outwardly spreading and mounding plant habit; moderately vigorous growth habit; freely branching habit with short internodes; dense and bushy appearance; plants require minimal pruning; flexible lateral branches that resist cracking and splitting; relatively small and dark green-colored leaves; color is maintained during the winter and under low and high light conditions; freely flowering habit with flowering continuous during the spring and early summer; strongly fragrant single white-colored flowers that become yellow in color with development; and excellent garden performance and temperature tolerance.