Purple Loosestrife (1 of 2) (IMAGE) Harvard University Caption Purple loosestrife, an invasive plant species common in the northeastern United States, is seen near Concord, Mass. Credit Abraham Miller-Rushing Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.