Thomas Rainer presents a powerful alternative to traditional horticulture: designed plantings that function like naturally occurring plant communities.  He is a landscape architect, teacher and writer, and has designed landscapes for the US Capitol grounds, the Martin Luther King, Jr. Memorial, and the New York Botanical Garden,  Hear him speak on Saturday, April 9 at 1 pm at Tower Hill Botanic Garden, 11 French Drive in Boylston.  A book signing will follow the talk.  Tower Hill members $20, nonmembers $30.  Register at www.towerhillbg.org.