Arboretum Bulletin Summer 2020, Volume 82, Issue 2 | Page 17

Asian maples such as the full moon maple (Acer japonicum) form one of the Garden’s core collections. (Photo by Chie Iida) Pines and other trees are expertly thinned and shaped each year to perfect the vision of the Garden. (Photo by Michael Lee) needed to fit into and contribute to the overall quality of the Garden. After the initial round of refinements, the focus shifted to the conifer canopy. Trees that were crowding the composition—or were out of scale or disconnecting the Garden from the borrowed scenery of its surroundings—were assessed for removal. An oversized cryptomeria in the Tea Garden and Alaska cedars (Cupressus nootkatensis) by the East Gate are examples of the removals from this era. At the same time, pruning to emphasize the structures of smaller trees was stepped up, helping to create a feeling of depth not dependent on volume. The thoughtful restoration of negative space helped to make the Garden feel larger, rather than sparser. (Note: The removal of large trees from such a carefully curated space presents a series of technical challenges for our crews and contractors. A great deal of thought, planning, and highly skilled execution goes into all of our decisions around the large tree collection here.) Ground covers were also changed, moss was encouraged, and the negative space between the ground plane and the tree branches added to the feelings of depth. As the first decade of the 2000s came to end, the addition of the gatehouse, Tateuchi Community Room, and new entrance plantings added to the growing narrative of the Garden. Hakone grass (Hakonechloa) and mondo grass (Ophiopogon planiscapus, as well as O. japonicum ‘Nana’), added texture outside the gate and tied the landscape to the architecture. NEW AND FUTURE PLANTINGS Nowadays, we select plants for their holistic contribution to the Garden. Recent additions include upright varieties of maples (such as Acer palmatum ‘Aconitifolium’), which connect the upper and lower stories and soften the dark, dense appearance of the conifer canopy. They also include osmanthus, such as Osmanthus fragrans, to supplement azaleas as low, textural evergreen foundational plantings or replace azaleas growing unhappily in wet, heavy soils. Conditions in the garden are not static. The removal of some large trees has changed patterns of light and rainfall, as well as the absorption and translocation of groundwater. On a larger scale, weather patterns are changing in ways that are difficult to predict: Groundwater and air quality are affected as our environment becomes more urbanized, and as more and more pests and diseases are being introduced. Adaptation is a key factor in the selection of new plants. Some species are showing increased susceptibility to pests and diseases (for example, shore pine and flowering cherries), while other species are not thriving in current conditions. As we look for replacements—or for enhancement planting material—we are seeking species for the future. Summer 2020 v 15