Sleuthing challenge M. Salicifolia: Made in Japan?

M. salicifolia by Karl E. Flinck hybrids are described under the M. saliiifolia heading. ln a written communication that I have received Which cultivars or possible hybrids from Professor S. of salicifolia Maximowicz Kawakami, previously in charge of Nikko should be chosen for our gardens? Botanic Garden, he mentions that a natural M. " M. salicifolia, in the botanical and salicifolia M. kobus hybrid has been described from horticultural literature, is treated in a North Honshu under the name x variable way with regard to that M. differ from the classical concept of the euchlora Momiuama. I have not had species. the opportunity to check the literature The treatment of M. salicifoliak for a description and the validity of the is best studied in: Latin name. Donald " ~ S. Spongberg's Wyman, in his book, for American Gardens, " mentioned Hard& in Temperate North America under M. salicifolia that particularly ~ S. Spongberg's Magnolia Salicifoliai nice specimens were being grown in the A n A rboretum Introduction Morton Arboretum and Swarthmore ~ C. Christensen's Magnolia Kobus og College. Magnolia Salici%lia Maxim Finally, a number of our society They both indicate a number of members have written in our journal quantitative characteristics, but also about M. salicifolia, its hybrids and seems conclude that only the leaf shape and forms. It as if most of those lower leaf surface pubescence are writers accept the occurrence of M. salicifolia diagnostic for the species and allow for hybrids. correct identification. In addition to written comments, I would like to mention two verbal Spongberg, who normally has a wide ones. Brian is species concept, says: "While the Mulligan convinced that the clone "Else Frye" putative hybrids involving M. is a true M. salicifolia. Phil salicifolia mentioned above do not Savage considers that he grows a M. salicifolia in his appear (based on the type specimens Bloomfield Hills He and/or plants) to be hybrids but only garden. is, variants of M. salicifolia itself, more study is definitely needed to fully resolve this problem. " Christensen has limited himself to establishing the differences which, in his opinion, separate M. kobus and M. salicifolia as species. He has, however, told me verbally that he considers some growing in my Swedish garden to be hybrids between M. salicifolia and M. kobus. In the 8th edition of Bean's "Trees M. 'Joe McDaniel, 'a newli and Shrubs Hardy in the British Isles, " introduced Gresham hi hrid. l7 wide range of soils and exposures. Since it has been impossible for me, in cold climates, to trace mature specimens raised from Japanese seed, I must conclude that M. salitifolia is either cold sensitive or in other respects quite demandmg. For M. salicifolia plants of proved Japanese origin I have noticed a much slower growth than for plants originating from Western gardens. In M. 'Todd Gresham, 'another newly my Swedish garden M. ~ kewensis is introduced Gresham hybrid. the fastest growing one of all magnolias. It has. over a 20-year however, surprised at the types of period, reached a height of 12 m. progeny he receives (not M. salicifolia- whilst over the same period M. .sali- like), also when no other pollen rifolia was only between 3-4 m. It took spender is present. M. sal'tci foha in Kew Gardens 60 years My own observations are based on to reach a height of l2 m. Of all living material that I have grown in my named M. "salicifolia" clones, only Swedish garden, and what I have seen 'Else Frye' is a fatrly slow grower. during trips to Denmark, England, I should also like to pomt out that Germany. Switzerland and USA. K. Wada has claimed that it was In my Swedtsh garden, I have grown impossible to grow M. salicifolia in hts three plants, which originated from two Yokohama nursery. shipments of wild Japanese seed. They The true Japanese-originating M. flowered when only 30 cm. high. I have salicifolia has very flowers, lost two of the plants, which died for floppy which stand badly agamst bad unknown reasons, and the third one is up The I have seen also have recovering after having been smashed weather. plants flowers with narrow tepals. All by a falling . cultivars I have tried have larger Of plants that have originated in flowers with broader tepals that stand Western gardens I grow or have grown ' better against bad weather. the following; M. 'Else Frye, M. 'Miss up ' Jack, M. & kettensis (nomen nudum), How can those differences in appear- ' M. 'Iufer, M. ~ proctoriana, and M. ance and behaviour be explained? 'Wada's ' Memory. I am inclined to accept the indirect I also have seedlings raised from evidence that M. kobus is involved in seed harvested in Phil Savage's garden most, if not all, cultivars. M. kobus is and in Morton Arboretum. easy to cultivate, is very cold hardy, I have trees recetved from the tolerates fairly hot climates, and has in German nurseries Hesse and Bolje as some of its forms large flowers and M, salirifolia. broad tepals. I have seen M. salicifolia plants in that M. 'Wada's England and Switzerland that are of It is interesting Memory' was introduced from Japanese origin. Elsewhere I have only Japan found plants that originate from as M. kobus. Western gardens. Where originally Based on my own and other people' s plants were introduced from Japan or cultural experiences, I would raised from wild collected seed, they all recommend the following to those who seem to have disappeared. wish to grow M. salicifolia or use it for Spongberg states that M. saluifolia hybridization: Stay away from plants plants appear to be very tolerant to a of Japanese origin; for fast growth and 18 either support or refute my position concerning M. v prortoriana. Moreover, it would be nice to involve society members in some of this problem solving, particularly since these aspects of this problem are aspects in which most are proficient and interested. I' ll be interested in your thoughts concerning this request. " References Bean. W. J., 1973. Trees and shrubs hardy in ' M. 'Sweet Sixteen, newly introduced the British Isles ed. 8 Gresham h rbrid. Christensen, C. . (980. Magnoha Kobus D. C. og Magnolia satieifoha Maxim. - to large trees use: M. 'Wada's Memory' or naertbeslaegtede Japanske Magnolia- M. x kewensis; for smaller space and arter. Dansk Dendrol. Arsskrift still beauty; M. 'Else Frye' or M. 5(3): 42-57 "salicifolia" from Hesse. Mxi xiii ix: Journal of the American Magnolia Society. Vols. II I. I. V III.2. IX. I. I have a hope that M. biondii will XIV. I, XV. I. XVI. I. XVII. I. produce larger flowers than M. Spongberg. Stephen A. Magnohaceae hardy salicifolia. If this wil! be the case, a in temperate North America. Journal of hybrid between the Hokkaido form of the Arnold Arboretum. Vol. 57. No. 3, M. kobus and M. biondii could be July (976 something to shout about. Spongberg, Stephen A. Magnolia salici- Steve Spongberg has kindly read this folia: An Arboretum Introduction. article before publication and made a Arnoldia, Vot. 41, 14o. 2, Mar. ~ plea for interested members to make Apr. 1981 controlled crosses. I cite from his letter: Wyman, Donald, 1951. Trees for American gardens "Concerning your paper, I found it very interesting and certainly think the I society should publish it in Maonoi un You did leave the Spongberg references out of the bibliography, but that, obviously, is just an oversight. The one plea that I really wish you would make is for one (or more) of the members who grows Magnolia kobus and a "good" M. salicifolia (based on leaf shape and pubescence) to make the appropriate crosses and grow hybrid progeny to document both the fact that hybridization is possible and the morphology and behavior of the progeny. If such a hybridization program were undertaken. an important aspect would be to prepare voucher specimens of both parents as well as of progeny as they develop and come into flower. The results, of course, would help enormously to explain the situation you described in ' your paper. It could also help resolve M. 'Lisa Odenwald, newly the "kewensis" problem as well as introduced Gresham hybrid. 19