November/December 2002 Excerpt

Excerpt from Cold-Hardy Camellias by Kathleen Fisher

Thanks to the work of two devoted plant breeders, gardeners in cooler regions can now enjoy these elegant fall- and spring-blooming shrubs.

Just as you can’t say “goatee” without stroking your chin, it’s almost impossible to say “camellia” without a southern accent. If you grew up north of the Mason-Dixon line, you may have worn ‘Pink Perfection’ to a long-ago prom; it probably seemed as exotic as a rain-forest orchid. If you hail from the former Confederacy, however, camellia growing may be a competitive sport, with face-offs between miniatures like ‘Man Size’ or the cabbage-size blooms of Camellia reticulata cultivars.

In the last two decades, an effort has been underway to change the camellia's image, with two breeders in particular working to prove that the camellia can be a tough landscape workhorse rather than just a pampered show-pony.

Lucky Disasters

It was unexpectedly harsh winters in the South and Mid-Atlantic that hastened two breeders toward producing camellias that would survive outside Scarlett O’Hara territory.

Clifford Parks had started his career in the early 1960s at the Los Angeles State and County Arboretum. There’s only one camellia he knows of that isn’t completely hardy there, so to test for cold tolerance his program had to ship all their plants to cooperators around the country, such as Longwood Gardens in Pennsylvania. In 1967 he moved to the University of North Carolina (UNC) and what seemed to be an only slightly more challenging environment, with tens of thousands of camellias in tow.

Then in 1985, the temperature in Chapel Hill dropped to 9 below, breaking the all-time record by nine degrees and killing 98 percent of two acres of camellias to the ground. Among the survivors were several selections of tea-oil camellia (C. oleifera), already known to be tough, but also some of the more showy Japanese camellia (C. japonica). From these came Parks’ spring-blooming ‘April’ series, introduced into the trade beginning in 1995.

In all, Parks has named almost 100 varieties, but says even the most reliable of them shouldn’t be considered bulletproof north of the warmer half of USDA Zone 6—what earlier USDA hardiness zone maps called Zone 6b. Although the most recent version of the USDA hardiness map no longer shows the division of zones into two parts, the distinction between “a” and “b” zones pops up often in the debate about where camellias will grow and bloom reliably.

Says Parks: “The new breed of camellias is just one step hardier” than their traditional growing region—a line he describes as running from Winston-Salem, North Carolina, to Richmond, Virginia, and up along the Atlantic Coast through Washington, D.C., to Long Island—“although some people make claims to more.”
Parks, who is now professor emeritus at UNC, doesn’t want buyers misunderstanding the difference between plant hardiness and bud hardiness, particularly among spring-flowering camellias, whose buds have to withstand the vagaries of winter. But even if plants are root hardy, winter damage can range from flowers that bloom but look ragged and burned, through totally blitzed buds or scattered stem dieback, to the shrub dying all the way to the ground.

"People at the Arnold Arboretum outside Boston tell me, ‘Sure, we can grow camellias—as herbaceous perennials,’” Parks relates. “If you live where the temperature goes below zero frequently, you should be growing something else.”
A half dozen years before Parks’ pivotal freeze, a series of mean winters had wiped the U.S. National Arboretum’s collection of 956 mature plants down to fewer than a dozen bedraggled specimens. Only one plant remained blemish free and blooming its head off—a C. oleifera received from China in 1948. Asians had been cultivating the species for some 5,000 years, not for show—since its flowers are unassuming—and its leaves rather small, but for its seed oil, which they used for cooking and cosmetics.

Nonetheless, this climatic misfortune switched research horticulturist William Ackerman and his colleagues into high gear. “We became opportunists,” he says, capitalizing on this plant’s acclimatization through a broad swath of Asia over the past several centuries. In the quarter century since, he’s found that first survivor, later named ‘Lu Shan Snow’, and a second, C. oleifera ‘Plain Jane’, to be perfect progenitors of exceptionally cold-hardy landscape plants when crossed with showier autumn- and spring-flowering camellias.

Just as Parks is known best for his spring-flowering C. japonica ‘April’ series, Ackerman is most famous for his C. oleifera fall bloomers. You’ll usually recognize them from the word ‘Winter’ in their cultivar name, although there are exceptions like ‘Ashton’s Pride’ and ‘Ashton’s Ballet’, which are named for the Maryland farm to which he’s now officially retired. In all, Ackerman can claim introducing 24 fall bloomers and 11 spring-flowering camellias in the trade.…

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Sources:
Camellia Forest Nursery, Chapel Hill, NC. (919) 967-5529. Catalog $2.

Growing Camellias in Cold Climates by William Ackerman. Noble House, Baltimore, Maryland, 2002.


Photos are by April Snow (David Parks) and Ashton’s Ballet (William Ackerman)