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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Gardens Unit » Research » Research Project #435609

Research Project: Establish and Maintain Public Display Gardens for Woody and Herbaceous Landscape Plants

Location: Gardens Unit

2019 Annual Report

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. [NP301, C1, PS1A] 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. [NP301, C2, PS2B] 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.

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 planting of wild-collected germplasm in the Springhouse Run Stream Restoration site was completed. The plants were grown in previous years from wild populations located within a 100-mile radius of Washington, DC. The Friends of the National Arboretum wrote a successful grant that has led to District of Columbia government support for ongoing surveillance and removal of invasive non-native plants in the site. Planting of the ecological layered design of the front portion of the Friendship Garden was also completed. Oaks and magnolias that are part of the Woody Landscape Germplasm Repository were included in the design. The previously renovated back portion of the garden received some redesign to address flaws in the original design. With regard to Objective 2, two interpretive panels were installed in the site to provide information about the Springhouse Run Stream Restoration to arboretum visitors, and knowledge regarding stormwater management was shared in a session at the American Public Garden Association Annual Conference. A concept for interpretive signage has been developed for the Friendship Garden. Under Sub-objective 2.a., the Beer Garden Exhibit was developed in the entrance of the National Herb Garden. The exhibit serves as a focal point for interpretation regarding Agricultural Research Service work in breeding hops, The Agricultural Research Service’s yeast germplasm collection, and the range of plants used to brew and flavor beer and related beverages. Under Sub-objective 2.b., ongoing support has been provided to researchers in the Invasive Insect Biocontrol and Behavior Laboratory in Beltsville, Maryland, and the Beneficial Insects Research Laboratory in Newark, Delaware, in utilizing the grounds of the USNA for research related to biocontrol of landscape pests. A program featuring advances in the management of Emerald Ash Borer was conducted in conjunction with the Beneficial Insects Research Laboratory and was attended by designers, urban foresters, and landscape maintenance personnel.

1. Germplasm acquisition, distribution, and incorporation into collections. The Gardens Unit enriches the living plant display collections at the U.S. National Arboretum by incorporating documented germplasm into the garden. We have added 815 new accessions to the living collections this year. A total of 29,134 living plants comprise the collections managed and are represented by 17,673 accessions. The records for 4,805 of these accessions were edited. Holdings are now available in Germplasm Resources Information Network (GRIN). The multi-site National Collection of maples was added to the American Public Garden Association Plant Collections Network.

2. Evaluation of germplasm for commercial production. A Monarda fistulosa accession collected in 2010 has been deemed to have commercial potential. Rosemary, dogwood, and Microbiota germplasm is currently being evaluated by nursery industry collaborators. The dogwood selection is resistant to Discula anthracnose and powdery mildew and has potential as breeding stock that may revitalize commercial production of dogwoods. The rosemary has enhanced winter hardiness and may extend the range of cultivation of the species.

3. Dissemination of plant information to the public. Visitation to the arboretum has increased in recent years by 20%; more than 600,000 visitors were hosted in the last year. The arboretum hosted more than 500 staff from public gardens across the country as part of the American Public Garden Association’s Annual Conference in June. The new Arboretum App was downloaded by 5,874 users and greatly enhances access to holdings data. 702 people registered for fee-based educational programs that generated more than $26,000 in income. 5,029 new display labels were completed and installed in the gardens and collections. A Beer Garden exhibit was developed and installed in the entrance to the National Herb Garden to highlights plants used in the brewery industry and features the hops breeding and germplasm preservation efforts of ARS.

4. Springhouse Run stream restoration. Springhouse Run is a typical stressed urban stream. The portion of the stream above the Arboretum is contained in storm sewers and the waters are polluted with trash, hydrocarbons, and untreated household sewage from illicit connections to the storm sewer system. The Arboretum partnered with the District of Columbia Department of Energy and Environment to restore the stream and planting of the restored area was completed this year. A total of 29,591 plants have been planted and 8,233 of those were planted this year. All plants were sourced as seed from wild populations within a 100-mile radius of the site to achieve a genetic resource for native plants like that which may have existed prior to disturbance.