1. What makes it easier for invasive plants to invade?
Desired Vegetation (plants you want!)
Ask your students, knowing what they do about how plants grow and reproduce, and plant competition, if they can think of some factors that make it easier for invasive species to move into a new area and replace native or other desirable plants. Have them brainstorm and use this concept map or handouts to come up with as many factors as they can think of. (Some factors include: removal or disturbance of existing vegetation and soil through trampling, driving, development, road-building; overgrazing by wildlife or livestock; and seed introduction by animals, humans, or vehicles such as bikes or cars moving from weedy to non-weedy areas.

2. What might decrease invasives and help desired vegetation return?
INVASIVE PLANTS
Desired Vegetation (plants you want!)
Factors include removal of invasive species through mechanical, chemical, or biological control, targeted grazing, controlled burning, preventing weed seed spread, education, revegetation with desirable plants.

3. Invasive Plant Management
WHY? Federal and state laws regulate the spread and control of Noxious Weeds in Montana. Invasive plants also cause many problems for humans and the environment.
WHO? Weed management is the responsibility of private landowners, various branches of federal, tribal, state, county and city governments, non-profit organizations and concerned citizens.
HOW? The most successful management programs integrate a variety of methods and approaches for managing weeds.
Among many other reasons to control invasive plants, it is mandated by law. 3

4. Integrated Plant Management
The best strategies to use will depend on the weed species, the area, the goals for management, the resources, and many other factors . It may include some or all of the following methods of weed control:
Prevention
Mechanical
Biological control
Targeted grazing
Prescribed burning
Chemical (Herbicides)
Restoration
Photo by Todd Breitenfeldt, WHS science teacher.

5. Prevention
Prevent weeds from entering an area by promoting weed-free forage, weed-free gravel, cleaning shoes and tires, boats, and pets, and minimizing disturbance to existing vegetation and soil.
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

6. Prevention
Prevent weeds from entering an area by promoting weed-free forage, weed-free gravel, cleaning shoes and tires, boats, and pets, and minimizing disturbance to existing vegetation and soil.
Pros: Stops the problem before it starts; low cost and little or no negative environmental side effects; can work anywhere. Long-term solution.
Cons: Only effective before plants invade. Education can be time-consuming.

7. Mechanical Control Pulling Mowing Tillage Digging
Oldest method of weed control
Pulling
Mowing
Tillage
Digging
Photo John Byrd, Mississippi State University
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

8. Mechanical Control Pulling Mowing Tillage Digging
Oldest method of weed control
Pulling
Mowing
Tillage
Digging
Photo John Byrd, Mississippi State University
Pros: Quickly effective on tap-rooted or newly established weeds.
Cons: Does not work on rhizomatous plants or on large infestations, disturbs the soil making it susceptible to new weed seed invasions, impractical over large areas and natural areas.

9. Photo Gary Piper, Washington State University
Biological Control
Uses natural enemies of weeds (such as insects) to attack, weaken, and often prevent the reproduction of invasive plants.
Photo Gary Piper, Washington State University
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

10. Photo Gary Piper, Washington State University
Biological Control
Uses natural enemies of weeds (such as insects) to attack, weaken, and often prevent the reproduction of invasive plants.
Photo Gary Piper, Washington State University
Pros: Good for large infestations with minimal effort and low cost. Very long-term.
Cons: May have unintended undesirable effects on other species. May not effectively reduce weed populations.

11. Grazing Control
Carefully timed and site-specific grazing by livestock (usually sheep or goats) to target consumption of invasive plants
Photo USDA ARS
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

12. Grazing Control
Carefully timed and site-specific grazing by livestock (usually sheep or goats) to target consumption of invasive plants
Photo USDA ARS
Pros: Good for large infestations with minimal effort and cost. Can help meet other needs of livestock producers.
Cons: May negatively effect non-target plant species. Not practical in all areas. Does not usually eradicate all plants.

13. Photo David Cappaert, Michigan State University
Prescribed Burning
Burn vegetation under carefully controlled conditions to control invasive plants
Photo David Cappaert, Michigan State University
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

14. Photo David Cappaert, Michigan State University
Prescribed Burning
Burn vegetation under carefully controlled conditions to control invasive plants
Photo David Cappaert, Michigan State University
Pros: Can impact a large area quickly; can have other positive environmental effects.
Cons: Many invasive species are fire-resistant; burning involves risk to other resources; may allow new invasive species to colonize area.

15. Photo James Miller, USDA Forest Service
Chemical Control
Herbicides stop or slow the growth or reproduction of plants:
Selective herbicides kill only certain kinds of plants such as broadleaf plants (non-grasses)
Broad spectrum herbicides kill any plant they contact
Photo James Miller, USDA Forest Service
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

16. Photo James Miller, USDA Forest Service
Chemical Control
Herbicides stop or slow the growth or reproduction of plants:
Selective herbicides kill only certain kinds of plants such as broadleaf plants (non-grasses)
Broad spectrum herbicides kill any plant they contact
Photo James Miller, USDA Forest Service
Pros: Often quickly effective and at times selective against just target species. Can be low cost; can impact large area quickly.
Cons: May have adverse effects on human and environmental health if not used properly; can be expensive; can have nontarget effects; weeds may evolve resistance to herbicides over period of time. Some cannot be applied near water. Re-application usually necessary.

17. Site Restoration
May include planting native or other desired species, stabilizing soil, tending and protecting newly established vegetation, and altering site management
Photo Las Vegas Wash Project Coordination Team
Pros: CAN YOU THINK OF PROS TO THIS METHOD?
Cons: CAN YOU THINK OF CONS TO THIS METHOD?

18. Site Restoration
May include planting native or other desired species, stabilizing soil, tending and protecting newly established vegetation, and altering site management
Photo Las Vegas Wash Project Coordination Team
Pros: Prevents future invasions; has other positive environmental effects. Long-term effects.
Cons: May be costly and time-consuming; takes a while to become effective.