On Saturday, May 7 beginning at 2 pm at Tower Hill Botanic Garden, 11 French Drive in Boylston, author and garden historian Marta McDowell will show us how the White House grounds reflect America’s enthusiasms, from George Washington’s obsession with collecting trees to Michelle Obama’s kitchen garden.  The talk and book signing is free with admission, but pre-registration is required.  Register at www.towerhillbg.org or call 508-869-6111, ext 124.