Hibiscus Hibiscus rosa-sinensis 'Mongon' is also known as Red Dragron™. It has spectacular double red flowers all summer long which contrast with the dark green foliage. The petals are wavy with very faintly visible veins. This is a tender evergreen shrub or small tree which stands 6 – 8 ft tall and is hardy to zone 10. It was bred from an hibiscus from southern China which is now believed to be extinct in the wild.