It’s a familiar sight all over town as a small street tree or a decorative shrub in commercial planters. Home gardeners love it as well, probably because the flowers are so showy and come in myriad warm colors. Bright yellows, vibrant corals, flashiest reds, and everything in between, hibiscus flowers can’t be missed. A few years back, hibiscus was a problem child, though. When the giant whiteflies arrived in town, it found these evergreen shrubs just to their liking. With the release of a predatory wasp and the finding that worm castings incorporated into the soil under the plants can lend control, the whitefly menace is somewhat abated. It is once again possible to grow healthy and beautiful hibiscuses. Other beneficial insects find the flowers a good source of nectar and pollen without doing any damage at all, so hibiscus is a good choice to foster them.
The hibiscus that most know by that common name are hybrids and selections of Hibiscus rosa-sinensis. This long-lived shrub can be almost tree-like in old age and warm climates. Where temperatures fall below freezing for prolonged periods, hibiscus can also be grown in containers and moved indoors in winter. The large, glossy leaves give it a very bold and tropical look. Add to that the funnel-shaped flowers that are four to eight inches across and the effect is dramatic and stunning. There are lots of named varieties to choose from with flowers that are single to extremely double. Some have ruffled edges of a different color to add even more interest. Even the compound reproductive parts are decorative.
What many gardeners in warmer climates don’t know is that there are other showy members of this genus that hail from cooler climate zones but will perform well here, too. The marsh mallow, Hibiscus moscheutus, lent its name to a confection that was originally made from its roots. It is native to Europe but has become naturalized over much of the eastern United States. As its name implies, it likes damp conditions and can even grow in standing water. Marsh mallow is a perennial that dies back in the winter. In summer it can grow to six to eight feet in height by three feet wide. The flowers are huge, as much as a foot in diameter, and come in shades of white, pink, and red. Some may have a different colored “eye” in the center, and petals may be ruffled or smooth. Shop seed and specialty nursery catalogs for named selections or try your luck with open pollinated seed.
Another hibiscus relative is known as Rose of Sharon. It is probably not the one mentioned in the Bible, but Hibiscus syriacus is an old garden favorite. Rose of Sharon is a deciduous shrub that can eventually grow to 10 or 12 feet in height by six feet wide. With pruning, it can be kept smaller. Pruning hard in winter will also improve the size of next year’s flowers. The flowers are numerous and about three inches across. Most are pastel shades of pink, rose, and purple and may be single or double-petaled. As with other mallows, they may have a red center or eye, increasing their charm. Preferring hot summers, Rose of Sharon can also take some drought, so it is especially useful in the hotter, interior areas.
There are two less well-known hibiscuses that might grow tolerably well in southern California. Hibiscus schizopetalus is native to tropical east Africa where it can grow to 15 feet high and 12 feet wide. Here, it is unlikely to be so large and pruning to keep its weeping habit looking graceful will produce a much smaller shrub. The flowers of this species, known as fringed hibiscus, have petals that are deeply divided, and they hang down rather than facing up or out. These frilly blossoms come in shades of pink or red as well as pure white and even yellow.
Jamaica flower, Hibiscus sabdariffa, is also known as Roselle. The flowers are not particularly showy but are grown for their fleshy sepals. This outermost whorl of the flower is harvested and eaten fresh or dried for later use. It makes a refreshingly tart beverage. Mexicans know it as agua de jamaica, and the dried flowers can be bought in the spice section of local markets. Since it takes a long warm season to begin flowering, it will most likely be a disappointment along the cool coast.
Add some drama to your garden with one or more of these mallows. They’re sure to attract the attention of insects and humans alike.