The Arboretum has a long history of serving as a source of plant distribution as a result of the staff’s ability to collect and grow a diversity of plants from a wide variety of sources. This provides an opportunity to share the benefits of these efforts, helps to preserve germplasm, and introduces a wide gardening audience to new and unusual plants. Over the past decade, some of the most significant of the distributions have included the following species:
Of the many taxa collected by the Arboretum over the past twenty years, few arouse more excitement among professional and lay horticulturists than Corylus fargesii. The trees display exquisite, exfoliating tan and copper bark that rivals the most attractive birches, and is especially reminiscent of river birch (Betula nigra). The Arboretum, with a NACPEC team, collected seed of this species in China in 1996 and 2005, and trees grown from these collections can now be found throughout the Arboretum. In the mid-1990s, seedlings were given to numerous botanic gardens, resulting in the widespread distribution of this highly desirable species. Several years ago, seed from the 1996 trees was collected and began to germinate; this has been so successful that this past January, seedlings were sent to eight organizations, ranging from Massachusetts to Minnesota and south to Georgia.
Native Canada hemlock (Tsuga Canadensis) has been afflicted by hemlock wooly adelgid, resulting in the severe decline of native and cultivated populations across the central and southern portions of its native range. Chinese hemlock is resistant to the adelgid, providing an opportunity to function as a replacement for Canada hemlock in cultivated areas, and to possibly breed resistance into the native species.
Prior to the late 1970s, Chinese hemlock appears to have only been introduced into North America only once. Beginning in the early 1990s, the Arboretum and its NACPEC colleagues made a concerted effort to introduce this species. These efforts resulted in 33 collections of Chinese hemlock, the addition of 55 plants to the Arboretum’s own collections, and numerous seedlings being distributed to botanical gardens. The most significant of these distributions has been to the Arnold Arboretum of Harvard University, to whom 96 plants were provided during the past 10 years.
In recent years Anthony Aiello, the Director of Horticulture and Curator, has focused on Japanese flowering cherries and has surveyed public gardens in the northeastern U.S. to find rare and unique varieties. The goal of this project is to propagate and re-distribute the plants to a wider audience of public gardens and private collectors. This effort has resulted in a fast turnaround and this past spring, nine varieties propagated over the past three years were distributed to the Scott Arboretum and the New York Botanical Garden. The results of this work were recently published in Arnoldia.