Of the more than 200 species of hibiscus in presence, some are hardy as far north as U.S. Department of Agriculture plant hardiness zone 5. Others can only endure winters in the warmest parts of the USA, and are generally grown as houseplants. The hardiness of outside hibiscus plants is dependent on where they originated, together with many deriving from North America, China, Africa or Australia.
Hibiscus types native to the United States of America include giant rose mallow (Hibiscus moscheutos), Texas star (Hibiscus coccinea) and Hawaiian white hibiscus (Hibiscus arnottianus). Giant rose mallow, which survives outside to USDA zone 5, was originally pink or white. It’s branched out into other colors as the ancestor of the contemporary hardy hibiscus. Texas star, together with narrow-at-the-base red petals, is hardy to USDA zone 7. These hibiscuses don’t flourish in Mediterranean climates, but as both are swamp species and need lots of moisture. Hawaiian white hibiscus, one of the few fragrant types, is just perennial to USDA zone 9 but makes a sweet-scented houseplant.
Chinese hibiscuses include Rose of Sharon (Hibiscus syriacus), which contrasts with the less hardy Confederate rose (Hibiscus mutabilis) and the far less hardy tropical hibiscus (Hibiscus rosa-sinensis). All three come from both single or double-flowered types. Rose of Sharon flowers in hues of pink, white, and purple, and is hardy to USDA zone 5. The confederate rose’s blossom mutates from white to pink to red over the course of a day, and the plant is perennial to USDA zone 8. Tropical hibiscus offers a wider array of colors than the others, but is just considered reliably hardy to USDA zone 10. It is, therefore, frequently grown as a container plant which can be brought indoors when required.
Many Australian hibiscuses prosper in Mediterranean climates, being well adapted to dry conditions. Australian rosella (Hibiscus heterophyllus) and hollyhock tree (Hibiscus splendens) both offer large flowers to compensate for their prickly leaves, and are hardy to USDA zone 9. The prior plant boasts a wider array of colors — pink, white, and yellow — while the hollyhock tree originally stuck to pink. It’s been crossed with Australian rosella in recent years, however, to create hybrids of many colours. Flower-of-an-hour (Hibiscus trionum) is also an Australian native. Although grown as an annual in most zones, it grows into a small shrub in USDA zones 9 and upwards. Just like the majority of hibiscus kinds, its cream-colored flowers only last for one day.
Cranberry hibiscus (Hibiscus acetosella) flaunts showy — and edible — maroon leaves. Although hardy to USDA zone 8, it does not show its purplish blooms until fall, therefore it is most commonly grown for its foliage. An annual in spaces under USDA zone 10, roselle (Hibiscus sabdariffa) blooms late too — in yellow with maroon calyxes which are used for flavoring teas and jellies. Another African native, deceptively known as Japanese lantern (Hibiscus schizopetalus) to get its hanging pink or red flowers, is only hardy to zone 10 and is most commonly grown as a houseplant.