The International Camellia Society [ Trailer ] [ Hardy Camellias ]

C AMELLIAS FOR C OLD C LIMATES William L. Ackerman Reliably COLD-HARDY camellias have long been a dream of northern gardeners. Even in the milder areas of the mid-Atlantic region of the United States, where camellias have been grown for many years, cold hardiness has become a concern.  At the U.S. National Arboretum, in Washington, D.C. (USDA Plant Hardiness Zone 7a, to -17E Celsius, where I conducted my research on camellias, we would occasionally get a hard winter freeze that did some plant damage, but rarely would any of the spring-blooming Camellia japonica or fall-blooming C.sasanqua cultivars be killed. Farther south, damage to the plants themselves was almost unknown, although there were cases of flower bud injury. The whole concept of cold hardiness changed for us following the winters of 1977-78 and 1978-79, when temperatures fell as low as -19E C, accompanied by strong, drying winds. Among the arboretum's nationally recognized collection of more than 900 specimens, most C.sasanqua cultivars were killed outright that first winter, and the C.japonica cultivars were badly injured. Even C.japonica cultivars considered to be the most hardy, such as 'Berenice Boddy', 'Governor Mouton', 'Kumasaka', 'Lady Clare', and 'Pink Perfection', were devastated. By 1980, the arboretum's once outstanding collection had been reduced to a half-dozen struggling plants and sprouting stumps. There was, however, a notable exception: a specimen of the fall-blooming C.oleifera, a white-flowered species introduced in 1948 from northern China. It came through both of those brutal winters unscathed and has done so every winter since, blooming normally despite severe temperatures. As a result, it was later named 'Lu Shan Snow' in recognition of its Chinese origin. Camellia oleifera is widely grown in the Orient, not as an ornamental, but as a source of seeds, which are pressed to produce cooking oils. (Indeed, the Latin epithet oleifera means  "oil bearing.") The oil is also used as a hair dressing and in cosmetics. The plant's virtues as a cold-hardy parent, however, were not immediately obvious: although this camellia makes a handsome evergreen shrub with an upright habit and glossy dark green foliage, its single flowers shatter badly when cut and even when left on the plant. Nevertheless, given the proven hardiness of the arboretum specimen, it seemed only natural to test other sources of this species. We secured eight strains of C.oleifera that had been collected throughout the Orient. Of these, only one was comparable in hardiness to our plant. In time, it proved even hardier than 'Lu Shan Snow', and was named 'Plain Jane', as its flowers were not as attractive as those of 'Lu Shan Snow'. Once we had established that 'Plain Jane' and 'Lu Shan Snow' would make the best parents, the breeding program began in earnest. Between 1979 and 1981, 10,000 controlled crosses resulted in 2,500 interspecific hybrids involving C.oleifera and various C.sasanqua and C.hiemalis cultivars. A second series of crosses between 1980 and 1984 resulted in more C.oleifera hybrids. This time, however, spring-flowering parents, including C.japonica and C.x williamsii were used. In addition, a series of C.oleifera hybrids I made in 1969 during a species-compatibility study were back-crossed to C.oleifera. The entire group was greenhouse grown until 1982 and then planted out for field testing at 14 locations including Pennsylvania, Maryland, Virginia, Western North Carolina, and the District of Columbia. Protection from the elements varied at the individual sites, ranging from an over-story of mature pines or deciduous trees to lath and shade houses. Comparisons between the hybrids of 'Plain Jane' and 'Lu Shan Snow' over the years proved that the former conveyed a greater degree of hardiness to its progeny. We made a second series of crosses between 1980 and 1984, which resulted in more C.oleifera hybrids.  This time, however, spring flowering parents including C.japonica and C.x williamsii were used.  Field evaluation and selection among these hybrids is still being carried out, so several years will be needed before any of these are named and introduced. Since 1982, the breeding program has concentrated on evaluating individual plants at the various locations for their cold hardiness. Thus far, they have experienced minimum temperatures ranging from -20E to -27E C. The most severe tests occurred during January 1985, and again in January 1994. Temperatures in each case had been moderate (5E to 10E C), and then suddenly plunged to between -23E and -28E C. Testing and evaluation has been an on-going process for the past 23 years. Individual cultivars are classified as hardy at a specific minimum temperature, if they show no more than 5% leaf burn after repeated exposures to that minimum temperature. We have concluded that the fall-blooming hybrid camellias are most valuable as landscape plants, attractive as their flowers are.  In the landscape, they are far more appealing than most cultivars of C.japonica: Their leaves are smaller and, in most cases, a shiny dark green.  Most will also flower at an early age -- some the second year from rooted cuttings.  And although they are not meant to produce show flowers, they will not all shatter after being cut, unlike most C.sasanqua cultivars.  In fact, the cut flowers of certain hybrids can last as long as four days. Following periodic relatively mild autumns, these hybrids begin to flower in my Maryland garden in early October, and the plants will have at least some blossoms out every week through the first week in January. During November and December, we normally have some hard freezes that brown all the open flowers. However, following a change to more moderate temperatures, many of the more immature buds will come into bloom. I have concluded that most of the breeding and development work for cold-hardy hybrids will never be completed. Although there is now a substantial group of these plants that is capable of withstanding comparatively severe winters, and of bearing flowers of equal or better quality than those of existing C.sasanqua cultivars, new and better ones keep coming along. In selecting hybrids worthy of commercial distribution, we have made an effort to provide a diversity of flower and plant forms. The flower shapes include single, semi-double, formal double, peony, anemone, and rose forms, in colours ranging from white through various shades of pink to lavender, and more recently, reds. In view of their landscape potential, we have selected plants which fall into six basic shapes without pruning. These are: prostrate, globular-round headed, irregular-spreading, upright spreading, upright columnar, and upright fastigiated (erect, rising to a pointed tip). Thus, hopefully, there will be a specific cultivar best suited for every special location or situation a gardener may have. Twenty-year old specimens can, depending upon the cultivar, range in height from three to fifteen feet. These cultivars are now being successfully established in areas where camellias were not previously grown outdoors. The New England region of the U.S. has never been considered "camellia country," yet these plants are thriving in coastal regions of Connecticut, Rhode Island, and Massachusetts. A hardy camellia is no longer a dream. Gardeners who live in areas where the winter extremes do not fall below -26 degrees C (Zone 5b), and where some protection from winter wind and early morning sun can be provided, should be encouraged to try these durable and exciting hybrids. William L. Ackerman, a Research Geneticist, retired from the U.S. National Arboretum in Washington, D.C., still maintains an active interest in hybridization and propagation. The following cold-hardy hybrids from the U.S. National Arboretum's Breeding Program (34 fall-flowering and 15 spring-flowering selections) have been named and are available from many retail nurseries.   Fall-flowering varieties   'Ashton's Ballet' -- C.japonica  'Shikishima' x C.oleifera 'Plain Jane' . Compact, moderately upright, average growth. Makes a beautiful garden specimen. Flowers are two-tone pink, rose form double. Blooms from early November to late December. Cold hardy to -23° C. 'Ashton's Cameo' -- C.hybrid 'Winter's Charm' x C.oleifera 'Plain Jane' . Moderate, spreading, compact growth, medium green foliage. Flowers are deep lavender pink, semi-double to loose peony form, notched petals. Blooms from November into December. Cold hardy to -23° C. 'Ashton's Pink' -- C.japonica 'Billie McCaskill'  x C.oleifera  'Plain Jane' . Dense, upright, average growth, dark green foliage. Forms a symmetrical plant without pruning. Flowers are lavender pink, semi-double, Long blooming season from December to February. Cold hardy to -23° C. 'Ashton's Prelude' -- C.oleifera 'Plain Jane' x C.sasanqua 'Setsusan'. Compact, slow to medium globular growth, dark green leaves. Flowers, shell pink, anemone form, floriferous. Blooms from mid October through November. Cold hardy to -23° C. 'Ashton's Pride' -- C.oleifera 'Plain Jane' x C.sasanqua  'Santozaki'. Vigorous, spreading, small narrow, leathery, medium-green leaves. Heavy bud setter. Flowers are pale pink, single. Blooms from mid-November to mid-December. Cold hardy to -26° C. 'Ashton's Snow' -- C.japonica  'Billie McCaskill' x C.oleifera 'Plain Jane' . Moderate, globular, dense growth. Leaves thick, leathery, semi-glossy, dark green. Flowers are white, semi-double. Long blooming season, beginning in early November and ending in late January. Cold hardy to -26° C. 'Ashton's Supreme' -- [C.hiemalis  'Bill Wylam' x C.oleifera 'Plain Jane'] x [C.sasanqua 'Narumi-gata' x C.oleifera 'Plain Jane']. Plant upright, dense medium growth, dark green foliage. Flowers deep lavender pink anemone to peony form. Very floriferous. Blooms from October through November. Very cold hardy to -27° C. 'Elaine Lee' -- C.japonica  'Mrs. Bertha Harmes' x C.oleifera 'Plain Jane' . Plant is compact, average vigor, upright in growth. Leaves dark green, glossy. Flowers are white, semi-double, especially hardy. Blooms from November, sporadically, through January. Cold hardy to -23° C. 'Fairweather Favorite' -- C.japonica 'Frost Queen' x C.oleifera 'Plain Jane' . Dense, upright, medium growth. Leaves leathery, glossy, dark green. Makes a very compact handsome specimen. Very floriferous. Flowers, white with pink underside, semi-double. Long blooming season from late-November through January. Cold hardy to -26° C. 'Frost Prince' -- C.hiemalis  'Shishi-gashira' x C.oleifera 'Plain Jane' . Moderately vigorous, globular growth. Very floriferous. Flowers are deep pink single to semi-double. Blooms from mid-October to November. Cold hardy to -20° C. 'Frost Princess' -- C.hiemalis  'Bill Wylam' x C.oleifera 'Plain Jane' . Compact, globular growth. Flowers are deep iridescent lavender pink, semi-double to anemone form. Blooms from early November to mid-December. Cold hardy to -20° C. 'Londontowne Blush' -- C.japonica  'Billie McCaskill' x C.oleifera  'Plain Jane' . Moderate, globular, compact growth. Flowers pale pink, single to semi-double, heavily notched petals. Blooms November to December. Cold hardy to -23° C. 'Polar Ice' -- 'Frost Princess' x C.oleifera  'Plain Jane' . Slow to moderate growth with arching branches. Flowers are white, anemone form. Blooms from early November to mid-December. Cold hardy to -23° C. 'Snow Flurry' -- C.oleifera  'Plain Jane' x 'Frost Princess' . Moderately vigorous, globular to spreading, with arching branches. Very floriferous, blooming at an early age. Flowers are white, full peony to anemone form. The earliest of the fall blooming series, it flowers from late September to mid-November. Cold hardy to -23° C. 'Winter's Beauty' -- C.japonica  'Billie McCaskill' x C.oleifera  'Plain Jane' . Compact, upright, moderate rate of growth. Flowers are shell pink with very light pink petaloids near center. Frilly, peony form. Very hardy flower buds. Blooms late November to-mid -January. Cold hardy to -26° C. 'Winter's Charm' -- C.sasanqua  'Takara-wase' x C.oleifera  'Plain Jane' . Upright, columnar growth, with leathery, glossy dark green leaves. Flowers are lavender pink, peony form. Blooms October through November. Cold hardy to -23° C. 'Winter' s Cupid' -- C.oleifera 'Plain Jane' x [C.sasanqua 'Narumi-gata' x C.hiemalis >  'Shishi-gashira']. Moderately upright growth. Leaves thick, leathery, semi-glossy, dark green. Heavy bud set. Flowers are white, flushed light pink near apex and on underside. Semi-double with curved and fluted petals with large central cluster of golden yellow anthers. Blooms late November through early January. Cold hardy to -26° C. 'Winter's Dancer' -- C.hiemalis 'Bill Wylam' x C.oleifera 'Plain Jane' . Spreading, slow growth. Flowers dark pink at center shading to light pink at margins. Semi-double to loose peony form. Blooms October to mid-November. Hardy to -23° C. 'Winter's Darling' -- C.hiemalis  'Shishi-gashira'  x C.oleifera 'Lu Shan Snow' . Moderately upright, slow growth. Leaves small narrow, leathery semi-glossy, dark green. Flowers are deep cerise pink, two-tone miniature anemone. Blooms from November through December. Cold hardy to -23° C. 'Winter's Dream' -- C.hiemalis 'Peach Puff' x C.oleifera 'Plain Jane' . Decidedly upright, vigorous growth. Leaves leathery, dark glossy green. Flowers are pink, semi-double. Blooms from October to November. Cold hardy to -23° C. 'Winter's Fancy' -- C.hiemalis 'Bill Wylam' x [C.hiemalis  'Shishi-gashira' x C.oleifera 'Plain Jane' ]. Moderately vigorous, upright and outward. This lends itself to uilization as a hedge plant. Leaves leathery, glossy dark green. Flowers are deep pink, semi-double, creped, floriferous. Blooms from October to November. Cold hardy to -20° C. 'Winter's Fire' -- 'Frost Prince' x C.vernalis 'Takarazuka'. Spreading growth with a weeping habit. Leaves semi-glossy, dark green. Flowers are medium, bright, reddish pink, semi-double with upright star-like creased petals. Blooms from November to January. Cold hardy to -20° C. 'Winter's Hope' -- C.oleifera 'Lu Shan Snow' x 'Frost Princess'. Moderately vigorous, upright growth. Leaves leathery, glossy, cupped, very dark green. Flowers, white, semi-double. Blooms from early October through November. Cold hardy to -23° C. 'Winter's Interlude' -- C.oleifera 'Plain Jane' x C. sinensis Rosea ("Pink Tea"). Moderately vigorous, upright, plant habit, lends itself to use as a hedge, since it tends to spread horizontally as well as being upright. Leaves leathery, glossy dark green. Flowers bright pink, anemone form. Blooms from November through December. Cold hardy to -26° C. 'Winter's Joy' -- [C.sasanqua 'Narumi-gata' x C.hiemalis 'Shishi-gashira'] x C.oleifera 'Plain Jane'. Vigorous, upright to columnar growth. Lends itself to making a tall, narrow hedge. Leaves leather, glossy, dark green. Flowers, bright pink, semi-double to full peony form, with wavy petal margins. Blooms from November through December. Cold hardy to -23° C. 'Winter's Moonlight' -- C.japonica 'Tricolor Red (Siebold)' x C.oleifera 'Plain Jane'.  Plant compact, average vigor, globular growth. Leaves dark green, glossy. Flowers are white, mostly single to anemone form. Long blooming season from early December through February. Cold hardy to -26° C. 'Winter's Peony' -- C.oleifera 'Plain Jane' x [C.sasanqua 'Narumi-gata' x C.hiemalis 'Shishi-gashira']. Excellent, bushy pyramidal form without pruning or shaping. Moderate to vigorous growth. Leaves leathery, glossy, dark green. Flowers medium to light pink semi-double, to mostly peony form, floriferous. Blooms from November through December. Cold hardy to -20° C. 'Winter's Red Rider' -- C.hiemalis 'Shishi-gashira' x C.oleifera  'Lu Shan Snow' . Very slow, dense, semi-dwarf -- makes a good patio plant or bonsai specimen. Leaves small, leathery, glossy, dark green. Flowers are lavender pink, single with notched petals. Blooms from Mid-October through November. Cold hardy to -23° C. 'Winter's Rose' -- C.oleifera 'Plain Jane' x C.hiemalis 'Otome'.  Plant similar to that of 'Winter's Red Rider'. Very slow, dense, semi-dwarf, with small leaves and small flowers, which makes it a good patio plant and is highly sought after for Bonsai purposes. Leaves leathery, glossy, very dark green. Flowers shell pink, formal double. Blooms from mid-October to early December. Cold hardy to -26° C. 'Winter's Snowman' -- [C.sasanqua 'Narumi-gata' x C.hiemalis 'Shishi-gashira'] x C.oleifera 'Plain Jane' . Vigorous, upright to columnar growth. Lends itself to making a tall, narrow hedge. Leaves leathery, semi-glossy, dark green. Flowers are white, semi-double to mostly anemone, slightly cupped. Blooms from mid-November through December. Cold hardy to -23° C. 'Winter' s Star' -- C.oleifera 'Lu Shan Snow' x C.hiemalis  'Showa-no-sakae'. Moderate to vigorous, upright growth. Leaves leathery, semi-glossy, medium green. Flowers are large, violet-pink, single. Blooms from very early-October through November. Cold hardy to -20° C. 'Winter's Sunset' -- C.oleifera 'Plain Jane' x 'Frost Princess'. Moderate, upright growth. Leaves dark green with light green margins. Flowers are medium, lavender pink, single, flat, crinkly. Cold hardy to -20° C. 'Winter's Toughie' -- C.oleifera 'Plain Jane' x C.sasanqua  'Jean May'. Slow to moderate growth, omewhat spreading. Leaves thick, leathery, glossy dark green. Flower buds very hardy. Flowers are lavender pink, semi-double, fluted and notched petals. Blooms from mid November through December. Cold hardy to -26° C. 'Winter's Waterlily' -- C.oleifera 'Plain Jane' x C.sasanqua 'Mine-no-yuki'. Slow to moderate globular form. Leaves thick, leathery, semi-glossy, very dark green. Flowers are white anemone to formal double, and appears to be more frost resistant even when partly open than most camellias. Blooms from November through January. Cold hardy to -26° C.   Spring Blooming Cold- Hardy Hybrids   'Arctic Dawn' -- C.x williamsii  'November Pink' x C.oleifera 'Lu Shan Snow' . Open, slightly pendulous growth. Leaves dark green. Flowers neon coral pink, large, 12 outer petals, then a row of petaloids, then a row of crinkly upright large petaloids with some stamens interspersed. Blooms late March through April. Cold hardy to -20° C. 'Betty Sette' -- C.japonica 'Frost Queen' x C.japonica  'Variety Z'. Compact, upright, average growth rate. Leaves broad, glossy, dark green. Flowers are medium pink, formal double of good substance. Late. Cold hardy to -23° C. 'Cream Puff' -- C.japonica  'Frost Queen' x C.japonica  'White Butterfly'. Vigorous, upright growth. Leaves glossy, dished, very dark green. Flowers are white, large, semi-double to loose peony, with good substance. Mid-season to late. Cold hardy to -20° C. 'Fire 'N Ice' -- C.japonica 'Tricolor (Siebold)' x C.oleifera  'Plain Jane' . Average, dense, upright growth. Leaves very dark green, semi-glossy. Flowers are dark red-pink, medium to large semi-double to rose form double. Blooms March-April. Cold hardy to -20° C. 'Frost Queen' -- Field trial selection from seed introduced from Northern Japan. Dense, upright growth. Leaves glossy, dished, very dark green. Flowers are white, large, semi-double with good substance. Mid-season to late. Cold hardy to -20° C. 'Ice Follies' -- C.x williamsii  'November Pink' x C.oleifera 'Lu Shan Snow' . Open, spreading, growth. Leaves dark green, semi-glossy. Flowers are bright pink, large, semi-double, crepe-like petals. Blooms March-April. Cold hardy to -20° C. 'Jerry Hill' -- C.japonica 'Frost Queen' x C.japonica  'Variety Z'. Average, dense, upright growth. Leaves broad, glossy, dark green. Flowers are rose pink, formal double. Late. Cold hardy to -23° C. 'Kuro Delight' -- C.japonica  'Kuro Tsubaki' x C.japonica  'Variety Z'. Slow, spreading growth of average density. Leaves dark blue-green, very long and narrow, peach-like in shape. Flowers are large, maroon red, semi-double to loose peony. Mid season to late. Long blooming season. Cold hardy to -26° C. 'Londontown' -- C.japonica  'Bertha A. Harmes' x C.oleifera 'Plain Jane' . Moderately vigorous, upright growth. Flowers deep red-pink, semi-double to loose peony, notched petals. Blooms March-April. Cold hardy to -20° C. 'Maroon Mist'  --C.japonica 'Tricolor Red (Siebold)' x C.oleifera  'Plain Jane' . Medium, upright growth. Flowers dark maroon red, large single to semi-double with large central cluster of deep orange anthers. Blooms April to May. Cold hardy to -20° C. 'Pink Icicle' -- C.x williamsii 'November Pink' x C.oleifera 'Lu Shan Snow' . Average, compact, upright growth. Leaves dark green, glossy. Flowers are shell pink, large to very large, peony form with large rabbit ears. Blooms February to March. Cold hardy to -20° C. 'Red Fellow' -- C.japonica 'Tricolor Red (Siebold)' x C.oleifera  'Plain Jane' . Spreading, semi-compact, medium growth rate. Leaves large, dark green, glossy. Flowers are bright neon red, large, semi-double, large yellow stamen center. Blooms April to May. Cold hardy to -20° C. 'Spring Cardinal' -- C.japonica 'Tricolor Red (Siebold)'  x C.oleifera 'Plain Jane' . Medium, dense, upright growth. Leaves dark green, semi-glossy. Flowers are Crimson red, formal double. Blooms February to March. Cold hardy to -23° C. 'Spring Circus' -- C.japonica 'Tricolor Red (Siebold)' x C.oleifera 'Plain Jane' . Medium, compact growth. Leaves, medium green, glossy. Flowers are semi-double and vary from solid red, white or pink, to stripes and blotches of deep pink on white background, all on the same plant. Blooms April to May. Cold hardy to -23E C. 'Spring Frill' -- C.oleifera 'Plain Jane' x C.vernalis 'Egao'. Slow, spreading growth. Leaves dull, medium green. Flowers are bright, iridescent pink, large, rose form double. Blooms April to May. Cold hardy to -23° C. Updated January 2006

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