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United States Department of Agriculture

Agricultural Research Service

Floral and Nursery Plants Research Unit


The U.S. National Arboretum's Floral & Nursery Plants Research Unit conducts research that has significant impact on many areas of agriculture, the environment, gardening, and especially the U.S. consumer.   For specific research details, please see the Scientists and their Specialties pages.  [You can also click here to see online versions of a few recent presentations].

Important research accomplishments include the following (with a summary of more recent accomplishments listed further below):

Arboretum bullet icon   Development of New Floral Plants & Production Protocols   

  • Chrysanthemum,  Poinsettia,  Easter Lily (1930s-60s)
  • New Guinea Impatiens (1970s)
  • Oxalis,  Clematis, Curcuma  (1980s)
  • Ornithogalum,  Daylily,  Lisianthus,  Lachenalia,  Cyrtanthus  (1990s)

Arboretum bullet icon   Development of Improved Landscape Plants   

  • Shrub Roses,  Glenn Dale Azaleas (1930s-60s)
  • Crape Myrtle Hybrids,  Holly,  Viburnum,  Hibiscus,  Pyracantha,  Crabapple,  Magnolia  (1970s-1980s)
  • Dutch Elm Disease-Tolerant Elm,  Maple (1990s)
  • Camellia,  Flowering Cherry,  Lilac,  Redbud (2000s)

Arboretum bullet icon   Discovery and Application of Biorationals For Insect and Disease Control  
(Natural Plant Compounds to Replace Chemical Pesticides)

  • Neem Oil products:   Rose DefenseTM  TriactTM   TrilogyTM

Arboretum bullet icon   Development of Diagnostic Techniques for Detection and Identification of Plant Diseases (1960s to present)   

Arboretum bullet icon   Development of Genetically-Engineered Virus-Resistant Plants   


  • Cultivars Released:
    • Five new disease- and/or insect resistant elm cultivars (e.g., 'Valley Forge', 'Patriot', 'New Harmony').
    • Four new insect-tolerant red maple cultivars ('Red Rocket', 'Somerset', 'Sun Valley', and 'Brandywine').
    • Several new cultivars of holly (e.g. 'Sky Pencil' and 'Sparkleberry').
    • Two flowering cherries ('Dreamcatcher', 'First lady').
    • A dwarf redbud ('Don Egolf').
    • A mildew-resistant lilac ('Betsy Ross').
    • Two dwarf crape myrtles ('Pocomoke'and 'Chickasaw').
    • Five new cultivars of Ornithogalum (the 'Chesapeake' series).
    • A daylily ('Chesapeake Belle').
  • Patents:
    • One Patent issued on a broad-spectrum potyvirus monoclonal antibody now available in a commericial diagnostic virus-detection kit.
    • Six Patents issued relating to the control of plant pests and pathogens with by-products of neem seed.
    • One Patent issued for clove oil as a fungicide to control soilborne and foliar pathogens.
    • One Patent issued relating to enhanced insect resistance in plants genetically engineered with a plant hormone gene.
    • EPA approved registration of Neem oil (see patents) as a biopesticide for non-food uses.
    • One Patent application relating to regeneration of roses from tissue culture.
    • One Patent applications on five cultivars of Ornithogalum.
  • Developed and utilized biochemical tests that more accurately identify true species of birch. Determined species distribution of specific plant compounds responsible for resistance or susceptibility to certain birch, lilac, and ash insect pests.
  • Developed DNA molecular markers to identify and differentiate species, hybrids, cultivars, and genotypes of various herbaceous and woody ornamentals.
  • Biorationals from a variety of plants, including Ardisia, Neem and Nicotiana, were developed and evaluated as biopesticides for the control of insects and fungi. New management practices for the control of whiteflies on ornamentals were developed.
  • Developed molecular tools for the successful detection and differentiation of (a) impatiens necrotic spot tospovirus, a serious viral pathogen of many ornamental and vegetable crops; (b) diverse strains of plum pox potyvirus, a serious viral pathogen of Prunus species; (c) viruses infecting Pelargonium; and (d) pathogenic and saprophytic isolates of Botryosphaeria, a pathogen of redbud (Cercis).
  • Developed molecular tools to detect the bacterial leaf scorch pathogen (Xylella fastidiosa) in: (a) new shade tree and other ornamental hosts; and (b) new insect vector species, including leafhoppers, spittle bugs and treehoppers.
  • Genetically engineered plants, using recombinant DNA technologies, to express viral and anti-viral nucleic acids, proteins and antibodies in plants, including Gladiolus, as a means to obtain virus resistance.
  • Produced mouse monoclonal antibodies and rabbit polyclonal antibodies to several plant viruses; including: Tomato spotted wilt; Impatiens necrotic spot; Cucumber mosaic; Cymbidium mosaic; Carnation necrotic fleck; Pelargonium line pattern; Lily symptomless; and Prune Dwarf; and many potyviruses). Antibodies have been donated to the American Type Culture Collection for public distribution and/or released to Agdia, Inc for commercialization (as part of a CRADA), or to the California and North Carolina State Department's of Agriculture for use in testing and certification of stone fruit trees.

Research Unit Home Page || Mission & Goals || History || Locations
Scientists & Specialties || Postdoctorals & Support Scientists || Technical & Support Staff
Recent Accomplishments || Publications & Patents || New Plant Introductions
Woody Landscape Plants Germplasm Repository || National Herbarium

Last Modified: 6/9/2011
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