Bachelor of Science, North Carolina State University, 1964; Master of Science, North Carolina State University, 1968; Doctor of Philosophy, Ohio State University, 1973.
Vocational agriculture teacher, Surry Center High School, Dobson, North Carolina, 1964-1969; agricultural extension agent, North Carolina Extension Svc., Dobson, 1969-1971; floricultural specialist, U. Georgia, Athens, 1973-1982; professor, head ornamental horticulture, U. Tennessee, Knoxville, since 1982.
Member American Society Horticultural Science (president Southern region 1991-1992), Professional Plant Growers Association (board directors 1988-1991), Bedding Plants International Board, Farm Bureau, Tennessee Nurserymen's Association (committees since 1982), American Horticulture Society.
Married Loretta Speaks, June 11, 1965. Children: Glenn Douglas Junior, Gena Denise, Lori Janette.