People have been moving plants and animals around the world for centuries. We all rely on plants from other regions of the world for food, construction materials, ornamental plants and fiber. Plants and animals that have been moved from their native habitat to a new location (a different ecological system other than the one in which the organism is naturally occurring) are referred to as non-native or exotic to the new environment. Most U.S. food crops and domesticated animals are non-native species and their beneficial value is obvious - corn, wheat and oats are examples. A small percentage of exotics cause serious problems in their new environments because they spread rapidly, displacing native plants and animals. They are collectively known as invasive exotic species.

Invasive plant infestations are often described as slow motion explosions. The plants typically exhibit the following characteristics:

• Rapid growth and maturity
• Prolific seed production
• Highly successful seed dispersal, germination and colonization
• Rampant vegetative spread
• Ability to out-compete native species
• High cost to remove or control

Invasive plants are rapidly becoming one of the earth’s greatest threats to biodiversity as well as a serious economic problem. It is difficult to determine the precise financial impact of invasive plants, but in the United States it is estimated to be upwards of $140 billion each year! This estimate includes the money we spend to find and remove them from public and private lands (how much money do you spend to control weeds in your lawn and garden?) as well as the costs associated with lost agricultural and forest productivity and public health.

Some 1,400 plant species are listed as invasive across the nation. In New Jersey, 29 invasive plants have been identified as widespread and 65 others have been identified as newly emerging, meaning that they are not yet extensively covering the state, but they are present and their populations are growing. Purple loosestrife (Lythrum salicaria) is one example of a widespread invasive. Native to Europe and Eurasia, this wetland plant is a perennial herb that grows four to ten feet high and sports striking magenta-colored flower spikes from July through September. In New Jersey, this plant is out-competing several important species of native plants which are essential for food and cover to native wildlife. Thus, we are not just losing native plants, we are also losing the animals which depend on them for food and shelter. Purple loosestrife can also clog drainage channels and irrigation ponds and reduce the capacity of wetlands to hold and absorb rainfall.