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Imagine for a moment what our yards and gardens across the North would look like without plants whose lineages trace back to Asiatic origins.
Imagine our gardens without Asiatic and Oriental lilies, peonies, lilacs, flowering crabapples, forsythias, flowering plums, clematis, garden roses, daylilies, hostas, or chrysanthemums. Most garden varieties within all of these groups owe their origins to East Asian species.
The names of Amur maple (Acer ginnala), Siberian larch (Larix sibirica), Manchurian ash (Fraxinus mandshurica), and Mongolian linden (Tilia mongolica) refer to their places of origin in Eastern Asia.
Common garden species such as Hosta sieboldiana, Lilium davidii, Viburnum sargentii, and Berberis thunbergii were named to honor botanical explorers who brought plants of Eastern Asia to the gardens of Europe and North America.
Similar Climates, Different Species
Plants have adapted to climatic conditions over millennia. While the cold continental climate is similar to the plains of North America, areas of Eastern Asia were not glaciated during the last ice age. As a result, those areas have great diversity in both the number of species and the genetic variation within species.
The wealth of Asian plants captured the imagination of gardeners in Europe and Eastern North America about 150 years ago, but many of the more winter hardy types only reached the plains and prairies of Canada and the central United States in the past 75 to 80 years.
Many Asian plants came to North America through the efforts of notable collectors such as E.H. Wilson and Joseph Rock who were sponsored by the Arnold Arboretum of Harvard University.
Its founder, Professor Charles Sargeant, recognized the potential of Eastern Asian plants for North America, and in addition to sending collectors to northern China, Siberia and Tibet, and other parts of eastern Asia, he encouraged others to collect and test plants from these regions.
In the 1920s Professor Neils Hansen of the University of South Dakota traveled to Manchuria and Siberia and established contact with A.E. Woeikoff, a Russian nurseryman and plant biologist who had moved to Harbin in the mid-1920s to manage a botanical garden and experiment station.
Mr. Woeikoff had studied in England and was fluent in English. He not only provided seeds of a wide variety of plants from the region to plantsmen in North America and Europe but also wrote about the potential of these plants for gardens in cold climates.
Correspondence and exchange of plants with Mr. Woeikoff ended in 1939 with the occupation of Harbin by Japanese forces. The exchange of plants with these areas has only recently resumed.
The significance of these exchanges to gardeners in North America can be appreciated by looking at examples of plant breeding that resulted in plant groups that are key to our garden designs.
Flowering Crabs, Lilies, Roses And More
First, we could look at the popular Rosybloom crabapples. This group was initiated by Isabella Preston when she crossed the Siberian crabapple (Malus baccata), originating in Siberia east of Lake Baikal, with the red vein crab, Malus pumila var. niedzwetzkyana, originating in the Caucasus Mountains of Western Asia.
Since her initial introduction in 1930, numerous varieties have been grown that have been selected for showy flowers, small and colorful fruit, tree form, and disease resistance.
The Asiatic lilies are another popular group of plants that owe their origins to species introduced from Eastern Asia. During the 1920s Miss Preston and Frank Skinner began hybridizing among the species Lilium dahuricum, L. davidii, and L. lechtlinii.
They also used L. elegans (L. hollandicum) which originated from gardens in Japan. These crosses resulted in plants with colorful flowers that were easy to grow in prairie gardens.
Many varieties have been developed since then with an incredible range of forms and colors. Perhaps the most significant development was a result of Dr. Patterson of the University of Saskatchewan incorporating the genes of L. cernuum into this group in the 1940s.
This resulted in a wide range of colors from white through pastel orange, pink, and yellow to purple. More recent lily breeding has been with the Oriental group and the trumpet and Easter lily (L. longiflorum) species (also originating in Eastern Asia).
While much of the breeding of these lilies has taken place in Canada and the United States, the geographic origin of the genetic material was in Asia.
Clematis x jackmanii, the best-known garden clematis, originated in England in 1860, from a cross between C. x hendersonii and C. lanuginosa, a large flowered species introduced to Britain from Eastern China by Robert Fortune ten years earlier.
Crosses and back-crosses with C. viticella have resulted in the large variety of large flowered clematis available today. More winter hardy cultivars resulted from hybrids between C. alpina (native to Europe and Asia) and C. macropetala (native of China and Siberia).
The first hybrid was Markham’s Pink developed in England by Ernest Markham. Many varieties suitable for northern gardens have been developed including Blue Bird, White Swan, and Rosy O’Grady by Frank Skinner and Ballet Skirt and Joe Zary by Stan Zubrowski of Prairie River, Saskatchewan.
Roses are another group where most modern garden varieties owe their origin to East Asian species. The most widely used species in the development of today’s roses are Rosa odorata, the Tea Rose that has long been cultivated in gardens in China and India, and R. chinensis semperflorens, the Chinese monthly rose.
Most winter hardy rose cultivars incorporate genetics of one or more of Rosa rugosa, R. laxa, and R. spinosissima altaica into their breeding.
For instance, later representatives of the Explorer series cultivars bring in R. rugosa from R. x kordessii, Rosa laxa from Suzanne and Simonet’s Masquerade x R. laxa hybrid and R. spinosissima altaica from Suzanne.
These are but a few examples of important plant groups that have come to us from Asia. The list of genera where we grow plants of Asian origin is very long and encompasses fruit (apricots, apples, pears, cherries) and other food crops as well as ornamentals.
The potential for the development of new cultivars from genetic material that is already in North American gardens is indeed very significant as is the potential to collect new material from the Asian source to find those types and strains that will be best adapted to our gardens.
And The List Goes On…
Plant genera with important garden plants of Eastern Asian origin include;