Purple Loosestrife is a widespread and serious problem affecting wetlands and lake edges. It tends to outcompete native plants for space and sunlight. It can change an open-water marsh into a habitat dominated by loosestrife in which the stiff plant stems are too dense to be suitable for waterfowl. Small pink flowers begin to bloom in July, first at the tip of the stem. Digging is strenuous but can work when the first few invaders appear. Cutting the stems before they go to seed is one way to drain the energy and control the growth of the colony. Seed heads need special handling; viable seeds in the soil may start new loosestrife plants.