Though spring seemed to get a bit of a late start in Boston this year, spring planting is already well underway at the Arnold Arboretum. Staff horticulturists are adding many trees, shrubs, and vines from our nurseries to their new locations in the landscape. This season’s additions to the living collection—including about 75 individual trees—represent plants collected on botanical expeditions, species of conservation value, and adjuncts to several of the Arboretum’s national collections and visitor destinations.
Among the “class of 2013” are young specimens birch (Betula spp.), hornbeam (Carpinus spp.), and holly (Ilex spp.), to name just a few. Many new accessions of species and ornamental roses will enhance new beds established last fall at the entrance to the Bradley Rosaceous Collection. Plants obtained on a 2008 staff expedition to the Adirondack Mountains are also finding their way into the landscape this spring, including red maple (Acer rubrum), mountain maple (A. spicatum), and two species of cherry (Prunus serotina and P. virginiana). The red maple, Accession #567-2008*B, was planted on Arbor Day during a special gathering and tour in the Maple Collection, and honors those who lost their lives or were injured in connection with the Boston Marathon bombing on April 15.
New maples represent an enhancement of the Arboretum’s “national collection” of the genus, grown in association with the U.S. Department of Agriculture. Other additions to Arboretum national collections include American beech (Fagus grandifolia) and two stewartias, mountain stewartia (Stewartia ovata) and upright stewartia (S. rostrata). An exceedingly rare species in the wild, S. rostrata was collected in China by Senior Research Scientist Peter Del Tredici, and joins a stewartia grove established near the burial ground on Peters Hill. Peters Hill will also receive 10 new individuals of Malus sieversii from Kazakhstan, believed by some to be the “progenitor apple” for all of our cultivated varieties.
The Arboretum’s horticulture staff plants mostly deciduous plants in the spring (April to early June) and coniferous plants in the fall (September to October). Trees growing in our nurseries that are intended for spring planting are dug before they leaf out, and planted in locations selected by the Curator of Living Collections and the Director of Operations. Once planted, new accessions are monitored closely by staff for their first few seasons until they are well established. If you’d like to spot the newest additions to our collections on your next Arboretum visit, look for young plants in the landscape marked by yellow-colored stakes.