DeWitt and Riska named to Advisory Council


The Delaware Botanic Gardens has added two new members to its Advisory Council, Henry DeWitt and Michael E. Riska.  The additions bring to fourteen the number of professionals who provide their expertise to further development of Delmarva’s first botanical garden. Delaware First Lady Carla Markell serves as chair of the Advisory Council.


The new members bring long service to the environmental community as well as nonprofit and financial management experience.


Henry DeWitt, of Henlopen Acres outside Rehoboth Beach, founded DeWitt & Associates, a company whose software is used by NASA ground networks to control satellites. In addition to currently consulting with NASA, he is a former commissioner of Rehoboth Beach who now serves on the Henlopen Acres Tree Committee. DeWitt is also a member of the Rehoboth Art League finance committee and is a former chair of its audit committee.


In addition, he is a member of the board of the Rehoboth Sister Cities organization, a former member of the Baltimore chapter of the Leukemia and Lymphoma Society and Baltimore Fund for Educational Excellence, and a volunteer with the Sussex YMCA masters swimming team. He holds a Ph.D. in computer science and plays bagpipes for local events.

Henry dewitt

Henry dewitt


DeWitt, whose ties to Rehoboth Beach go back thirty years, has lived full time in the area for twelve years. “My yard has become a gardening project designed to provide an environment friendly to wildlife and the environment,” he relates. “We have two loblolly pines that may be among the biggest in Delaware. And I’ve been raising our own fruits and vegetables most of my life.”


Michael E. Riska, of Hockessin, was awarded the Nature Conservancy’s Lifetime Conservation Achievement Award in 1997. He retired in 2011 as executive director of the Delaware Nature Society, where he had served since 1984, including directing its education programs. The Delaware Nature Society works to improve the environment through conservation, advocacy, and education.

Riska has also been honored with the Exceptional Leadership Award and the President’s Award from the Association of Nature Center Administrators in 1999 and the Delaware Center for Horticulture’s Mary Marsh Award for Horticultural Excellence and Service to the Community in 2015.


In retirement Riska has served since 2012 as a board member of the Delaware Nature Society, Delaware Center for Horticulture, Brandywine Baroque, and North American Clivia Society. He also advises groups including Children in Nature/No Child Left Inside and environmental studies programs at the Tatnall School (Greenville, Delaware) and Providence Country Day School (Rhode Island).   

Michael Riska

Michael Riska


Riska’s environmental education experience extends back to teaching positions with both the Delaware Nature Society and the Tatnall School, where he was a science teacher and middle school science department chair. He has served in addition as an associate professor at the University of Delaware.

A consistent blue-ribbon winner at the Philadelphia Flower Show and Longwood Gardens Clivia Show, Riska tends his personal native plant garden, which has been featured in the book The Living Landscape by Rick Darke and Doug Tallamy. He also volunteers at Longwood Gardens.

As Carla Markell, Advisory Council chair, notes, “The Delaware Botanic Gardens is fortunate to gain the wisdom of these talented people. I’ve had the pleasure of working directly with Mike Riska as cochairs of the Ambassadors Group for Children in Nature/No Child Left Inside. Both he and Henry DeWitt are environmental leaders and hands-on gardeners who will only enrich the programs of this exciting new garden in our state.”