Invasive plants are a special type of weed. A weed is a plant out of place. Invasive plants are from a different part of the world and so are very out of place. In their native location something limits their growth such as competition from other plants or insects that eat them. The this competition is absent from your lawn and garden so they can grow unchecked and cause a big problem.

Controlling invasive plants is a part of integrated lawn and garden pest management.

Removing invasive plants is a good example when it is environmentally responsible to use a herbicide. Invasive plants species can cause much more damage to an ecosystem than properly used herbicides.

However, resist the temptation to buy a shelf full of chemicals and use them all on one type of plant. Your local extension agent or the epa link below can help you find best way to control invasive species and other weeds in your lawn or garden.

Invasive plants are non-native plants that:

• grow aggressively or spread rapidly
• displace or out compete other plants, causing harm to our natural areas
• primarily exotic plants - those that originated in another part of the country or world

Why are invasive plants a concern? In their natural environment plants have evolved with other plants, animals, diseases, etc. forming a community (or ecosystem) that's in a state of balance. When plants are introduced from other areas, the complex interrelationships and balance may be disturbed. Exotic plants may sometimes spread out of control and overwhelm native vegetation. One of the more notorious examples is kudzu, a quick-growing vine that was introduced in the Southeastern U.S. as a quick-growing groundcover for disturbed areas like highway embankments. A native of Asia, it has now spread from East Texas to New England where it has smothered 7 million acres of forest. Other alien invaders were brought over as ornamental garden plants, including multiflora rose, purple loosestrife, Norway maple, oriental bittersweet and Japanese honeysuckle. The invasion by non-native plants is the second greatest threat to native species, after land clearance for development.

Other impacts from invasive plants include mixing with native plants altering their genetic makeup, harboring pathogens harmful to other plants, and producing toxins lethal to certain animals. When one species takes over a large area it can also alter hydrological patterns, fire regimes and soil chemistry, moisture-holding capacity, wildlife habitat, and erodibility. All told, invasive plants cause billions of dollars of damage each year and tens of millions of dollars are spent annually trying to control them.

There is some confusion and even disagreement about what plants are considered invasive in a particular area. Some plants are a serious problem in one area, but hardly so in another area nearby; this could be due to different soils, climatic conditions or other physical reasons or be a matter of time - how long an alien plant has been in the area. Secondly, many plant species have a number of cultivars and they may not all be invasive, or to the same degree. With new species and cultivars being introduced all the time and cross-pollination occurring, it's extremely difficult to have definitive information. Finally, it should be pointed out that many different invasive plant lists are published, both at state and regional levels, by government agencies and non-profit organizations. Because there are different interests involved, it's important to consider the source of the list. For example, state and county cooperative extension agencies issue lists that protect agricultural interests, while the U.S. Forest Service has silviculture (commercial tree growing) in mind with its list. Not surprisingly, there is not total agreement regarding invasive plants for a particular area.

With this said, there's enough agreement from scientists and resource managers across the board, that invasive exotic species are a very serious problem and those plants that pose the biggest threat are uniformly listed by all agencies, organizations publishing lists. When considering your back yard or a specific site, it's best to start with a good regional source and then add to that other plants listed by state and local agencies or organizations.

The lists linked below are issued by federal agencies and non-profit organizations concerned with natural areas, native plants and endangered species protection.

What can you do to avoid or remove invasive plants from your lawn or garden?

• Don't disturb natural areas -- minimize clearing of native vegetation; don't dump yard waste in or near natural areas as it may contain seeds of invasive plants.
• Don't purchase or use invasive exotic species.
• Use plants that are native to your region or at least those known not to be invasive -- check lists of invasive plants from your state or local region (see below).
• Remove invasive plants entirely or manage them to prevent spreading (such as cutting off seeds).
• Discuss your concern about invasive exotic plants with nurseries and garden shops so that they are not sold.
• Notify land managers of invasive plants on their properties.
• Offer to assist in exotic plant removal projects from public property.
• Work within your community to encourage the use of native plants.

U. S. EPA - Invasive Non-Native Species