Location: Public Horticulture and Engagement Unit
2024 Annual Report
Objectives
Objective 1: Collect, propagate, preserve, evaluate, document, display, distribute, and introduce woody and herbaceous landscape ornamentals with enhanced aesthetic appeal, resistance to extreme weather, resistance to pests and diseases, and enhanced ecosystem benefits. Collection activities will focus on native plants due to difficulties with collecting plants in most other countries.
Objective 2: Disseminate scientific and practical information to floral and nursery crop industries, to public gardens, to the increasing number of visitors to the U.S. National Arboretum and its Website, and to the general public interested in gardening.
Sub-objective 2.a. Develop exhibits and interpretive signage that reflect current relevant ARS horticultural research programs, including the scientific mission of the U.S. National Arboretum.
Sub-objective 2.b. Develop educational programming to increase awareness of ARS research and germplasm preservation taking place at the U.S. National Arboretum.
Approach
The U.S. National Arboretum will continue to serve the public need for scientific research, education, and gardens that conserve and showcase plants to enhance the environment. This will be accomplished by maintaining outstanding gardens, plant collections, and public displays in an environmentally responsible and aesthetically pleasing manner. New ornamental cultivars and germplasm will be acquired using the Collections Policy and the newly developed Strategic Plan as a guide, and in support of the National Plant Germplasm System. Plants will come from nursery sources, wild-collected, or the USNA research program. Plants with superior landscape attributes will be propagated for distribution and evaluation. Staff will continue to utilize integrated pest management (IPM) in management of their collections and will explore the use or demonstration of other technologies such as solar power, green roofs, rain gardens, and water wise gardens as funds allow.
Plant records will be updated and coordinated with GRIN-global, and information will be uploaded to the publicly accessible Arboretum Botanical Explorer database. A new exhibit and educational program, GrassRoots, will be put in place. Educational opportunities will be optimized and implemented to provide formal and informal educational programming through exhibits, signs, publications, web pages, lectures, workshops, and tours. Volunteer and internship programs will continue to be supported.
Progress Report
Progress was made on all Objectives, which fall under National Program 301.
Under Objective 1 - The Gardens Unit enriches the living plant display collections and benefits global scientific research by incorporating documented germplasm into the gardens at the National Arboretum. The Unit is responsible for curating and maintaining thirteen Gardens and Collections on 451 acres. A systematic review of the plant collections and inventories to determine the value and scientific merit of the plants within our living collections was continued this year. Where accessions were not deemed worthy of continued cultivation, they were removed. We have made progress in writing the Collection Development Plans for eleven of our most vital collections, including Conifers, Native Plants, and our Asian and Azalea Collections. This effort included a more strategic focus and a direct link to and collaboration with the Arboretum's Floral and Nursery Plants Research Unit's Germplasm Project to tie the plant genetic resources of the Gardens Unit's Collections with the National Plant Germplasm System (NPGS). This included a minor reorganization and renaming of the Gardens Unit to the Public Horticulture and Engagement Unit [PHEU] in the 2nd quarter of 2024. The Public Horticulture and Engagement Unit continued the integration of our internal plant records database (BGBASE) with NPGS's Germplasm Resources Information Network (GRIN) Global Database, principally through the collaboration of the Floral and Nursery Plants Research Unit's [FNPRU] Germplasm Project Lead Scientist and Gardens Unit Botanist [who is now with FNPRU]. More than 1,690 Arboretum accession records and 7,572 plant (inventory) records were edited and updated in GRIN-Global this year.
More than 200 trees were planted in collections, and nearly all are growing well. We have added a total of 526 new accessions to the living collections this fiscal year. A total of 25,987 living plants comprise the managed collections and are represented by 14,627 accessions.
With a coordinated internal effort, the PHEU horticulture team completed the repairs and general upkeep of the arboretum's collections-focused irrigation system. This includes all of the major collections where irrigation has been built, as a functional system is essential for the continued long-term conservation of valuable plant germplasm.
Plants in the Springhouse Run Stream Restoration site are maturing, and the focus continues to center on removing invasive plant species. This year, the PHEU Horticulture team made significant inroads in removing invasive species and stabilizing Springhouse Run. Through a series of Group Projects, the team was able to create a sustainable landscape for 90% of the stream. Continued work in this area was suspended in late fall 2023 until the DC Department of Energy and the Environment reengages in the reoccurring issues of Springhouse Run.
Surveillance and removal of invasive plants throughout the Arboretum continue to focus on preserving gardens, collections, meadows, and woodlands at the U.S. National Arboretum. This effort is being done using a combined team approach, using the expertise of the Arboretum's horticulture team and the outside contractor Invasive Plant Control Inc.
The well-documented Oak decline in the Mid-Atlantic region is unfortunately prevalent at the National Arboretum, with mature trees of Quercus montana being driven to near extinction from the grounds. In an effort to understand the impact of this decline, a thorough survey of the nine species recorded to be native to the Arboretum has been ongoing. From this effort, three species, Quercus marylindica (Black jack), Q. palustrus (Pin oak), and Q. veluntina (Black oak), have been shown to be represented by a critically reduced number of trees.
From our cultivated Inventory, we continue to evaluate the horticultural merit of Rosemary (Salvia rosemarinus), American dogwood (Cornus florida), and Siberian Cypress (Microbiota decussata). American nursery industry collaborators are currently evaluating this germplasm. The American dogwood selection is resistant to several fungi (i.e., Discula anthracnose and powdery mildew) and has the potential as a breeding stock that may revitalize commercial production of dogwood. The rosemary has enhanced winter hardiness and may extend the range of cultivation of the species.
Under Objective 2 – A few examples of direct interaction of Unit staff with key stakeholders include, staff-led arboricultural tours of USNA Gardens and Collections; Washington Area Master Gardener Programs; a short course on plant identification; the 37th Annual Lahr Native Plant Symposium; a "Day of Arboriculture Symposium" for the Mid-Atlantic Chapter of the International Society of Arboriculture; and, hosted a visit and gave a grounds tour to participants in the Longwood Gardens Fellows program and the White House Leadership Development Program participants. Fee-based programs reached over 300 people, generating more than $15,000 (gross). Of particular note was a sold-out, fully bilingual Spanish/English half-day, hands-on workshop for landscape crew members. USNA staff taught basic identification of woody plants, an introduction to IPM, pruning best practices, and best practices regarding tree planting, watering, and mulching.
After several years of COVID-related hiatus in recruiting interns and volunteers, 14 interns and several new volunteers were onboarded.
Seven National Bonsai & Penjing Museum special events or exhibits were held in the Bonsai Museum during FY24, including 3 stakeholder-related exhibits. The main exhibit in the National Bonsai & Penjing Museum was Cultivated Stones: Chinese Scholars’ Rocks from the Kemin Hu Collection (November 4, 2023 – March 17, 2024). In honor of a generous gift from Kemin Hu, we filled our Exhibits Gallery at the museum with Chinese scholars’ rocks (gongshi) for an extended exhibition. It provided our visitors with the opportunity to step into the world of the Chinese literati– a mystical, magical landscape of inspiration and exploration. Accompanying the exhibition was a 152-page catalogue featuring 107 color photographs of the collection. The curator gave exhibit tours to seven groups, including the Asian American Forum, New Scottland Garden Club, and Freer Gallery docents. St. John’s College in Annapolis has requested loans from our collection for an upcoming exhibit at their museum. We also developed and presented a curriculum for "Bonsai Basics: Chrysanthemum Bonsai Course" [which is five classes conducted over the summer and fall of 2024]. We collaborated with the National Bell Festival organization to install their gift of a 225-year-old Japanese temple bell at the National Bonsai & Penjing Museum. A public dedication ceremony was held on New Year’s Day to ring in a year of peace. About 100 visitors attended on a day when the museum is usually closed.
Of special note, the National Bonsai and Penjing Museum worked with the U.S. State Department to hold a bonsai exhibition of 13 bonsai from Japan and one native species from the U.S. in three rooms within the state Department headquarters at 2201 CST, NW, DC. The exhibition was in preparation for an official state visit of Japanese Prime minister Fumio Kishida. The twelve trees from Japan included five bonsai that had been gifts between past Japanese Prime Ministers and U.S. Presidents. The bonsai native to the U.S. was a gift from American bonsai artist, Bjorn Bjornholm, who has owned bonsai nurseries in both the US and Japan. Notable attendees of the exhibition were Japan Prime Minister Kishida, U.S. Vice President Harris, and Secretary of State Blinken.
We are currently in the final stages of development a suite of interpretive signage and web/app content about the role of Civilian Conservation Corps [CCC] Camp NA-1-DC in developing the grounds of the US National Arboretum from 1931—1941. Primary source research was conducted at the National Archives National Personnel Records Center in St. Louis and elsewhere. Staff were able to locate and transcribe CCC service records for 196 members of Co. 1360 of Camp NA-1-DC, which was the first African American CCC camp in the Washington, D.C., area. Enrollees cleared and graded land, built bridges and roads, installed fencing, and planted the Arboretum's first nurseries, creating the backbone of the grounds as they still exist today. This collection of disparate primary sources was undertaken in order to share this hugely significant but little-known and under-valued facet of Arboretum history and to develop a cohesive narrative and establish the Arboretum as a central repository for information pertaining to Camp NA-1 and Co. 1360. Signage content has been finalized and panels are either complete or are in fabrication, with an unveiling event scheduled for November 2024.
Accomplishments
1. Integration of Arboretum internal plant records database into the national global database. The Public Horticulture and Engagement Unit has continued the incorporation and amalgamation of our internal plant records database (BGBASE) with the National Plant Germplasm System (NPGS) Germplasm Resources Information Network (GRIN) Global Database. This effort included a more strategic focus and a direct link to and collaboration with the Arboretum's Floral and Nursery Plants Research Unit's Germplasm Project to tie the plant genetic resources of the Public Horticulture and Engagement Unit’s Collections with the NPGS. ARS researchers in Washington, D.C., successfully added more than 1,690 Arboretum accession records and 7,572 plant (inventory) records to GRIN-Global this year.