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William H. Darr College of Agriculture

Pamela Borden Trewatha, Ph.D.

Professor Emeritus, Horticulture and Plant Science


New weeds, information being added to Midwest Weed ID link above during  the fall-winter of 2023- follow link for more information.

I am now retired, but still enjoy assisting in weed and other plant identification.  Please e-mail photos of any unknown plants/weeds to me at the address above, and I will respond as soon as possible.

E-mail is also the best way to contact me now for other inquiries.

Educational Background:

  • B.S. in Plant Protection, 1978, Purdue University, Department of Botany & Plant Pathology
  • M.S. in Horticulture, 1982, Kansas State University, Department of Horticulture
    • Emphasis on woody ornamental production; research on use of growth retardants on container-grown blue holly
  • Ph.D. in Horticulture, 1987, Kansas State University, Department of Horticulture
    • Emphasis on turfgrass physiology; research on enhancing spread and reducing water use of zoysiagrass cultivars by use of growth regulators       

Research Interests: (although retired, I'm still working on several research activities)

  • I'm currently working on writing a midwest weed identification manual and am continually researching and photographing weeds throughout the midwest
  • Surveys of new weed species spread in Missouri and throughout midwest
  • Native plant production, restoration and adaptation for use in ornamental horticulture
    • production and evaluation of prairie/dryland wildflowers for sustainable landscapes
    • evaluation of western native oak species for use in Missouri
    • root system development in oak seedlings to identify native oaks for successful inclusion in nursery/landscape industry
    • evaluation of spruce species for use in Missouri
  • Past research has included evaluation of native warm-season grasses for allelopathy, effect of herbicides on native warm-season grass mycorrhizae, turfgrass cultivar evaluation trials