On Friday, September 12, the Massachusetts Horticultural Society and the Perennial Plant Association are teaming up to offer a day-long symposium entitled Exploring Design & Perennial Selection for the Landscape. Some of the best writers and creative plantsmen and women in the business will be here, and you’re invited to listen, learn and ask questions. The event will take place at Elm Bank, 900 Washington Street in Wellesley, and the cost is $109. To register, or for more information, email kfolts@masshort.org, or call 617-933-4973.