There is a lot of concern today about invasive plants, but many were intentionally introduced because of their horticultural value. How do we define invasive and how did these plants get into our landscape? See examples in the Arnold Arboretum landscape and gain a better understanding of this issue. Led by Docent Marty Amdur on Saturday, August 7, from 1 – 2:30 pm, this program is free. No registration required.Â For more information, log on to www.arboretum.harvard.edu.