The present invention relates to a new and distinct cultivar of Hibiscus plant, botanically known as Hibiscus rosa-sinensis, and hereinafter referred to by the name ‘Adonis Yellow’. 
The new Hibiscus plant is a product of a planned breeding program conducted by the Inventor in Sabro, Denmark.  The objective of the breeding program is to create new strong Hibiscus plants with attractive and long-lasting flowers. 
The new Hibiscus plant is a naturally-occurring branch mutation of Hibiscus rosa-sinensis ‘Adonis’, disclosed in U.S. Plant Pat.  No.  21,592.  The new Hibiscus plant was discovered and selected by the Inventor on a single flowering plant within a population of plants of ‘Adonis’ in a controlled greenhouse environment in Sabro, Denmark in May, 2011. 
Asexual reproduction of the new Hibiscus plant by vegetative terminal cuttings in a controlled greenhouse environment in Sabro, Denmark since September, 2011 has shown that the unique features of this new Hibiscus plant are stable and reproduced true to type in successive generations.