Greg earned his degree in horticulture from Purdue University, focusing on aquatic plants and water gardening. In 1989, with wife Sue, he opened Crystal Palace Perennials in St. John, Indiana, USA. Crystal Palace listed over 400 varieties of marginal plants, a display pond with over 300 waterlily varieties, and advertised the largest selection of aquatic plants in North America. In 1996, Greg, along with four other water gardening enthusiasts, started Water Gardening Magazine. Greg co-authored several water gardening books, most notably the Encyclopedia of Water Garden Plants, with wife, Sue.
Greg served on the IWGS Board of Directors from 1997 to 2001, leading the Trials and Collections Committee for several years. Later, Greg became an innovative director of Hilltop Garden and Nature Center, a program of Indiana University in Bloomington. Greg introduced over 300 new hardy and tropical aquatic marginals and over 100 new native water plants to the water gardening industry.