Still crazy for begonias

We think we know begonias: those round waxen blobs with white or pink icing sold in six-packs; the speckled thing your grandmother grew or the gaudy plumed ornaments that thrive along the coast.

But the truth is, there are almost 2,000 official species of begonias, plus innumerable hybrids and cultivars. And while all of them have that distinctive elaborate foliage and are generous in their flowering, the variations are endless.

Begonia leaves may be green, red or almost black, often with one hue on top and another on the underside. They are frequently embellished with colored or silvery splotches or streaks. The edges can be wildly scalloped or bordered with toothy points. The surface itself can be smooth and shiny. Or waffled, or hairy or felty.

And then there are the flowers, borne in large drooping or airy upright clusters, the product of a rich history, growers’ creativity and the nurturing breezes of the California coast.

Europeans have studied begonias in this region of the world since the mid-17th century, when the first pressed specimen was sent back from Mexico. Over the next two centuries, plant hunters collected and returned with live plants from warm regions all over the globe. The craze had begun and has yet to wane.

Southern California became famous for begonias in the late 19th century, when pioneer nurserywoman Theodosia Burr Shepherd raised begonias outdoors here for the first time. A sickly mother of four, she single-handedly turned Ventura-by-the-Sea into the “Home of the Begonia.” Unfortunately, her vast collection was destroyed by root rot -- gardeners take note, it is the bane of the begonia still -- shortly before her death in 1906.

Begonia mania was revived in the 1920s by a San Diego County nurseryman, Alfred D. Robinson, whose gardens in Point Loma were said to grow the “finest begonias in the world.”

Owing to the gentle climate, new species are still found frequently in the wildlands, and busy breeders continue to create hybrids.

Such breeders -- or plant hybridizers -- are an interesting sort: part Dr. Frankenstein and part Michelangelo. Michael Kartuz, of Kartuz Greenhouses in Vista, is a respected nurseryman who dabbles with all sorts of rare and exotic flowering plants. Begonias are among his favorites, and he is especially praised for his dwarf and miniature hybrids. Kartuz also maintains what may be the largest collection of begonias in California.

Brad Thompson is another key breeder, now working out of Hi-Mark Begonias’ greenhouses. He raises thousands of begonia seedlings per year and concedes that success depends on luck, climate and patience. Despite the odds, Thompson has introduced more than 400 named hybrids since 1990.

Begonias are divided into five categories: cane, shrub, rhizomatous, tuberous and trailing.

In general, the easiest to grow are cane, shrub and some varieties of rhizomatous. They are the most tolerant of high temperatures, low humidity and less-than-rigorous attention. Although perennial, all begonias tend to rest in the winter and some even drop their leaves and go dormant.

In cultivation, begonias are propagated from seeds, which are minute, as well as from divisions, leaf or stem cuttings, or air layering. Most propagation is done during the warm months. Oddly, each begonia plant produces separate male and female flowers.

All outdoor begonias prefer dappled light but not deep shade, or direct sun in the morning or late afternoon. Those with dark foliage can take the most light. Few are forgiving of searing midday sun, though many cane begonias color up after a dose of strong sunlight.

Cane begonias are upright with bamboo-like stems and winged and spotted foliage. Dwarf canes make nice container subjects.

Shrub types offer incredible variety in leaf texture, color and shape, and in plant size and leaf size. “Shrubbies” are, perhaps, the easiest to grow and don’t tend to drop their leaves in winter.

Tuberous begonias are only happy in gardens close to the ocean. They are flashy and boast enormous flowers.

In nature, trailing begonias use aerial roots to attach themselves to trees. In gardens, they can be grown in hanging pots or go up walls.

Rhizomatous begonias are a little trickier. These low, spreading, ball-shaped plants can take the heat but not much light. They form dense clumps and are early blooming, with flower sprays that rise up and out over the foliage.

Water may be the begonia’s greatest foe. They are, after all, succulent plants and quite prone to rotting.

According to Mark Bartholomew, owner of Hi-Mark Begonias, they are more adaptable than people think. “Begonias need less water than impatiens and less humidity than fuchsias.”

Although they prefer to go almost dry between waterings, begonia roots demand fast drainage. In the ground, it helps to add plenty of compost or commercial planting mix. If your soil is really heavy, consider planting on mounds or in raised beds, or keep your begonias in containers. For pots, Kartuz recommends a porous mix with lots of fine bark and perlite or sand.

Mealybugs, aphids, spider mites, whiteflies and other small pests are occasional problems, especially on stressed plants or in gardens with poor air circulation.

To prevent fungus problems, Bartholomew emphasizes good sanitation, especially in the moist spring. “Remove lousy-looking foliage so light can get in, then new growth will develop at the bottom,” he said. “Weekly cleaning and pruning will greatly reduce disease.”

Ruth Wilson experiments with begonias in her 10-year-old garden in western Riverside County, where arid triple-digit temperatures are not uncommon. Her 110-plant collection includes dark-leafed cane types with pink and white speckles, some shrubs and even a few rhizomatous cultivars. All are sheltered from the midday sun.

She advises: “Go for it, just don’t subject them to the worst of conditions.”

And if the worst happens, you can always get another one.

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Sources for unusual varieties: Hi-Mark Begonias, www.himarkbegonias.com; Kartuz Greenhouses, www.kartuz.com.