Q Is this a rare Hibiscus brackenridgei?
Kath McNally, by email A
ANNE SAYS Having studied the photo of your lovely hibiscus, I’m not convinced it is H. brackenridgei – it is probably a hybrid of Chinese
H. rosa-sinensis. I would expect to see a pure yellow flower, of more rounded shape, and lobed leaves.
H. brackenridgei is one of the Hawaiian species, known there as
Ma’o hau hele and named after the Scottish-American horticulturist William Dunlop Brackenridge. The three subspecies reach tree-like heights of 10m and, as you rightly point out, all are endangered in their natural habitat (usually dry forest). The yellow hibiscus is the official flower of Hawaii and cultivated in gardens there.
You also ask how to propagate your hibiscus. I would take cuttings after flowering – removing a couple of shoots shouldn’t do it any harm and will encourage it to make new growth. Dip the cuttings in hormone rooting compound, provide gentle bottom heat and cover with ventilated polythene.
If you are an RHS member, take advantage of their plant identification service, or for help preserving rare plants, contact Plant Heritage’s Plant Guardian scheme at bit.ly/plant-guardians.