Join the Rose Kennedy Greenway Conservancy on Tuesday, August 10 for the next installment of the Greenway’s Horticulture Series: Urban Arboretum Tree Walk.  come along this walk to learn about sizes, blooms, and leaf shapes that one can enjoy in the park, or plant at home.  Assemble at the Greenway Tent, at Dewey Square, near the South Station MBTA.  Free.  For more information, log on to www.rosekennedygreenway.org.