James Luby and Emily E. Hoover with Bob Guthrie
Copyright Regents of the University of Minnesota. All rights reserved.
In Minnesota, the growing of cold-hardy kiwifruit spans three centuries. In one of the earliest accounts, Samuel B. Green, University of Minnesota’s first Professor of Horticulture in 1892 wrote:
A. arguta, wrongly called A. polygama. – A rampant growing ornamental vine from Japan. This has been grown in a small way by R. J. Mendenhall, of Minneapolis, [at the location of the present Lake Street K-Mart]and has been found to be unreliable. At the experiment station we lost ours the first winter it was planted.
The non-cold hardy Japanese plant material likely originated from one of Professor Green’s instructors at the Massachusetts Agricultural College (MAC, now the University of Massachusetts — where Professor Green received his degree in 1879). MAC President (as well as the Professor for Botany and Horticulture) William S. Clark brought back seeds of A. arguta and A. polygama that he collected in the forests near Sapporo, Japan in 1876. Upon his return a year later these seeds were grown were distributed to various horticultural societies, contacts, and academic institutions (Harvard’s Arnold Arboretum , Michigan State University , and plants were growing in Iowa by 1884).
In 1902 Professor Joseph L. Budd at Iowa State University wrote: Actinidia arguta. – This is a peculiarly rampant growing vine from Japan, with a tropical expression of foliage. Where hardy east of the [Great] lakes and in the South, it will cover a fence, arbor, or trellis in less time than any vine known to the writer. In the West, north of the 42nd parallel, [the latitude for Ames, Iowa] it is not hardy enough for a permanent covering of arbor or porch; but in less important positions, if cut back severely when injured, it soon regains what it has lost, with added beauty of the new growth.
In 1905 Professor Green wrote regarding vines growing on the St. Paul campus farm: A. arguta. A rank growing climbing plant from Japan. Foliage large, handsome, has never flowered at the University Farm but has held on well and made a vigorous growth each year. We cannot advise planting as there are more desirable vines.
In 1905, Professor Green apparently did not have access to more cold-tolerant genetic stock. At the St. Paul campus, minimum winter temperatures during the preceding two winters were -33 F and -26 F and it is likely that the Japan-derived plants that he had growing at that time were killed back to the snowline. In Minnesota A. arguta typically requires a minimum of two concurrent “mild” winters in order to flower as mid-winter temperatures below -25 F can produce vascular injury for most varieties of this particular kiwifruit species.
USDA-sponsored plant explorations in Russia and China during the first two decades of the 20th century introduced more cold-hardy plant material to North America. After Professor Green’s death in 1910 no further evaluations of kiwifruit were performed by the Minnesota Experiment Station until the mid-1980’s. However in Ottawa Canada (USDA Hardiness Zone 3b [-30 to -35 F]) the most cold-hardy of the kiwifruit species A. kolomikta was planted in 1897 and reported two years later as being hardy. In 1931 at the Morden (Manitoba) Arboretum (established in 1915 and also in USDA Hardiness Zone 3a [-35 to -40 F]) A. kolomikta was reported to be sufficiently hardy to survive the winters of southern Manitoba. Three Russian accessions obtained and planted in 1962 were still growing at Morden in 1970.