Charles Black’s fascination with hibiscus began while he lived in Hawaii, where he had developed skills in the propagation of tropical plants. He began an evaluation program to select cultivars offering the best flowers and the sturdiest growth habit. He then perfected a unique hibiscus grafting method that improves plant performance and simplifies their production. His Hidden Valley Hibiscus, Inc, is now the largest producer of exotic hibiscus, shipping over 50,000 plants to commercial growers for distribution throughout the United States and beyond. He shares with us the recent history of hibiscus, the problems associated with many available cultivars, and his own recommendations for the best of the best.
Hibiscus rosa-sinensis, commonly called Chinese or tropical hibiscus, has the unusual distinction of being a “manmade” plant. Although the genus Hibiscus includes hundreds of species found in tropical and temperate climates, most bear little or no resemblance to cultivated forms of H. rosa-sinensis, the most popular plant in the genus. The flowering plants we admire and grow today are the result of hybridization efforts by many people over the course of several centuries and in widely disparate geographical areas. Within just the last decade, new and exciting breeding work has begun to transform these lanky landscape plants into sturdy, compact, garden shrubs with sensational flowers.
In spite of the specific epithet, sinensis (meaning Chinese), most speculation now centers on India as the likely source of the earliest ancestors of today’s hybrid hibiscus. Hibiscus rosa-sinensis has not been found in the wild, but almost certainly originated somewhere on the Asian continent. One researcher, Ross Gast (see Fall ’89, p 47), sailed around the world in the early 1960s in an attempt to trace the origins of hibiscus. He believed that people leaving the Indian subcontinent and migrating through the South Pacific islands were the first to spread H. rosa-sinensis to other parts of the world. Nonetheless, it was in China that hibiscus were first cultivated extensively; many selections were discovered growing around temples and palaces there by European explorers and traders who brought hibiscus back to Europe. There exists a description and illustration of a double red hibiscus dating to 1678 and attributed to Van Reede (Rhee). In 1731 Philip Miller, curator of London’s Chelsea Physic Garden, brought a double red form and others to England. In 1810 John Reeves, an English tea trader and a Royal Horticultural Society member, commissioned a Chinese watercolor artist to paint various hibiscus cultivars he had seen in China. Hibiscus reached its height of popularity as a “stove plant” later in the nineteenth century, kept warm and flowering (or at least alive) in the kitchens of the time.
The peoples of Malaysia, Tahiti, Fiji, and Hawaii have all formed special relationships with hibiscus, incorporating them in their cultural and religious traditions. However, it was in Hawaii that the breeding of hibiscus really took off at the beginning of the twentieth century. The “native” forms (really imports from China and introductions by the Polynesians) were crossed with truly native Hawaiian hibiscus and with, notably, the split-petal species from East Africa, (H. schizopetalus). The resulting hybrids were spectacular compared with what had been seen before, and spurred an enthusiastic movement to create yet more hybrids. Gerrit Wilder organized the first hibiscus shows, beginning with one in 1914 that featured 400 selections. Thousands of new hibiscus were created in the following years, and in 1923, the Territory of Hawaii adopted the hibiscus as its official flower..
Eventually interest spread to the mainland United States, and in the early 1950s the American Hibiscus Society was formed, with the goals of promoting interest in hibiscus and establishing a centralized registration process for recording the names of new cultivars of Hibiscus rosa-sinensis. This effort has continued to the present, with similar efforts made simultaneously in Australia. Recently, a worldwide registrar was appointed with plans to combine the American and Australian nomenclatures. Since only a few people grow many of the named hybrids, they eventually disappear if no one propagates them. It has been estimated that as many as two-thirds of the named cultivars are either extinct or difficult to locate. However, with over 6,000 names registered, that still leaves a lot of hibiscus to choose from.
Hibiscus in the United States
No part of the continental United States is truly tropical, yet many areas have hot summers. Gardeners and designers in those regions had to choose the hardiest and most sun and heat tolerant cultivars to plant in their landscapes. They also wanted plants with a free-flowering habit. A relatively small group of cultivars made up their palette, including familiar names such as ‘Brilliant’, ‘President’, ‘Seminole Pink’; the list has changed little since hibiscus became popular landscape plants. Sturdy and floriferous, these are all vigorous growers quickly becoming large bushes. They remain the most familiar of all hibiscus cultivars, although there are many new and superior selections now available.
Hybridization of hibiscus has continued among small groups of enthusiasts, most particularly among those who compete in hibiscus shows in Florida, Texas, and Australia. While the “show” hibiscus and the “landscape” hibiscus share the same origins, it is only in the show hibiscus that significant progress has been made in developing new and improved cultivars. This has been possible, in part, by the use of grafting as a means of propagation, thus freeing the hybridizers to concentrate on flowers and growth habits without concern for strong root systems. Breeders now are concentrating on bigger and more beautiful blossoms. And they have succeeded wonderfully!
Unfortunately, many of the modern cultivars lack strong roots or a sturdy, upright habit. By grafting onto cultivars with good root systems, the problem of poor roots can be overcome. However, not much can be done about shrubs with poor branching, sparse foliage, or a floppy habit like that of a prostrate ground cover. Some selections can be trained as standards or espaliers, but many are simply not garden worthy.
Searching for the Best
For the first time in the United States, we have begun evaluating more than 1,000 cultivars with the most popular flowers. From these, we choose only the ones with acceptable—or better—growth habits to propagate for commercial distribution. We look for an upright habit, attractive and abundant foliage, a naturally branching response to pinching or pruning, good but not excessive vigor (to avoid soft floppy wood), and general good health and ease of cultivation. When we find a cultivar with these qualities and an exceptional flower produced in abundance, we make it part of our commercial propagation program. Our goal is to provide the public and other growers with the best of the many thousands of named hibiscus that have appeared over the last hundred years.
(We realized it would not be practical for us to hybridize for significantly better growth characteristics using the commonly available landscape cultivars. That would be a decades-long process with no guarantee of success. Ross Gast made such an attempt forty years ago, when he began breeding hibiscus suited to Southern California. He produced only one notable cultivar still in use, ‘Ross Estey’.)
We decided to look at the thousands of show hibiscus in hopes of finding some that could become good landscape plants. After five years of testing and evaluating, we have identified one hundred cultivars that are reasonably good, less than thirty that we believe are without major flaws, and fewer than ten that meet all our specifications. Over the next decade, we hope to collect or hybridize other cultivars to join the exclusive “Best of the Best” list. Meanwhile, we have begun making the top one hundred available to garden centers and other growers, while maintaining a larger list of “collector only” grafted cultivars that we produce on demand. (For a true collector, the blossom is usually the most important aspect of the plant, and we are happy to provide unusual and rare cultivars to those who do not mind their other shortcomings.)
Hibiscus for Containers
In Europe, breeders have concentrated on developing small, compact plants with many small blooms, to satisfy the demand for potted houseplants. These are also grown in the United States and are sold mostly in cold-winter regions. They are grown on their own roots, usually several plants to a pot, and are chosen based on their response to chemical plant growth regulators. When pinched and treated with a growth regulator twice, the result is a bushy, compact, attractive plant in a six-inch pot sporting plenty of buds and blossoms at the time it reaches the marketplace. The flowers are small and usually in solid colors, but the overall impression of a well-grown plant is pleasing and popular. These are “disposable” hibiscus, seldom likely to develop into healthy, long-lived plants, though they are pretty and may last for a season or two.
Through our evaluation process, we have also discovered fancier hibiscus cultivars that can be grown in six-inch pots. These are grafted selections with large, sophisticated flowers. They can be grown without growth-regulating chemicals, and can be expected to last for many years. They will outgrow the small pot within a year of purchase but, with care in watering and fertilizing, can be maintained in ten-inch or three-gallon pots indefinitely. They need one or more hours of direct sun to flower well, with temperatures in the 60s °F at night and warmer during the day.
Top Fifteen Hibiscus Cultivars
After ten years of evaluation, we feel comfortable in recommending the following cultivars of hibiscus. All have single (five-petaled) flowers, except as noted.
‘Amber Suzanne’ offers classic eight-inch, pink and white double flowers on a sturdy, full bush reaching six feet tall and wide. It flowers reliably, each flower lasting two days and is relatively tolerant of temperature extremes. AHS “Hibiscus of the Year,” 1993.
‘Bonnie B’, though slow growing at first, eventually becomes a strong, attractive bush with heavily textured eight- to ten-inch blossoms that can last up to three days if not in too much sun.
‘Crimson Ray’ is a well-branched shrub, with elegant eight- to nine-inch, maroon-throated, yellow flowers.
‘Dragon’s Breath’ has a deep red, eight-inch flower with pure white rays emanating from the center. It develops an upright bush to six feet tall in the ground, shorter in containers. Best in a mix of direct sun and shade, it will also grow in steady filtered light.
‘Fantasy Charm’ flowers steadily with pink and white eight- to ten-inch flowers and is tolerant of heat and sun. An upright bush to six-feet in the ground, it also grows well in containers. It is considered the best large-flowered cultivar.
‘Fifth Dimension’ flowers prolifically, its unusual eight-inch, gunmetal-gray flowers edged with orange-yellow edge; white flares radiate from the red center. A shrub to six feet in the ground, it will be smaller in containers. It tolerates full sun and heat. “Hibiscus of the Year,” 1989.
‘High Voltage’ has a bright red eye bleeding into the satiny, pure white, eight-inch flower.. The strong upright bush reaches eight feet in the ground. It is highly recommended for its steady flowering and toleratance of sun and heat.
‘Jami Lou’ produces bright eight-inch blossoms with a dark eye, red halo, pink body, and tan edge. These upright shrubs reach six feet tall in the ground and flower well in a mix of direct sun and shade.
‘Midnight Blue’ performs best in shade or filtered light where its unique eight-inch blossom of medium red and dark blue will not fade. It will grow upright to six feet in the ground and is also a good container plant. Second place 1998 “Hibiscus of the Year.”
‘Mystic Pink’ flowers steadily with attractive pink and white, eight-inch blossoms. A strong bush with large, attractive leaves, it grows upright to six feet in the ground. It grows well in containers and is somewhat heat- and sun-tolerant.
‘Rainbow Christie’ has an eight- to ten-inch pink flower with a large dark eye and a wide creamy-white border. An upright bush, it is highly recommended for its floriferous nature and moderate tolerance of heat and sun.
‘Red Snapper’ is the most popular double, with eight-inch, cherry red and white flowers and pronounced yellow stamens. Flowering prolifically and tolerant of sun and heat, this vigorous eight-foot shrub is highly recommended.
‘Silver Memories’ offers unusually subtle, silver and cream, eight-inch blossoms on an upright bush, six feet tall in the ground. It also does well in containers. “Hibiscus of the Year,” 1997 and “Judges Favorite,” 1998.
‘The Path’ sports an exceptionally large magenta eye in a distinctive eight-inch blossom of fuchsia pink and yellow. The upright bush reaches six feet and grows well in sun or shade.
‘Wheel of Fortune’ produces a subtle eight-inch flower in shades of lavender and red, fading attractively to pink and silver-gray. An upright bush to eight feet tall in the ground, it is somewhat tolerant of heat and sun.
To learn what local retail nurseries stock these hibiscus, grown on their own roots, see our website at hiddenvalleyhibiscus.com or call 760/749-6410.