Magnolia ‘J. C. Williams’ produces large, glowing red-purple flowers with pink interiors, which are bowl-shaped and can be as wide as 15cm. Magnolia ‘J. C. Williams’ blooms prolifically from an early age, typically in mid-spring. It has a large, upright and spreading form with an open and airy appearance. Magnolia ‘J. C. Williams’ is deciduous, not native to New Zealand, and a hybrid between Magnolia sargentiana and Magnolia sprengeri var. diva ‘Diva’. Magnolia ‘J. C. Williams’ was raised by Phillip Tregunna, the head gardener at Caerhays Castle in Cornwall, England. Julian Williams registered Magnolia ‘J. C. Williams’ and named it after his grandfather, who was responsible for planting the Caerhays garden.