Managing Invasive Plants: Concepts, Principles, and Practices link

U.S. Fish Wildlife Service
America's National Wildlife Refuge System

MANAGING INVASIVE PLANTS: Concepts, Principles, and Practices

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Physical Methods: Targets and Considerations

Appropriate Target
Key Considerations


  • taprooted and shallow-rooted terrestrial plants (particularly annuals) unable to resprout from roots or other vegetative organs can be hand pulled; larger plants can be pulled with tools such as a Weed WrenchT
  • shallow-rooted aquatic plants
  • pull when plants are big enough to grasp and soils are damp or loose enough to release roots
  • labor intensive, may need to be repeated
  • useful in small areas and areas inaccessible to large equipment
  • in aquatic situations, roots and all plant fragments must be removed from the water
  • pull and remove plants off-site when seeds can spread
  • very selective


  • annual and perennial plants that are unable to sprout from roots or other vegetative organs
  • hoe seedlings or small plants
  • labor intensive, may need to be repeated
  • useful in small areas and areas inaccessible to heavy equipment
  • very selective


  • annual plants
  • shallow-rooted perennials
  • till when weather is hot and soils are dry to reduce chances of resprouting or seed germination
  • with perennials, till when plant carbohydrate reserves are low (e.g., early spring)
  • most often used on restoration sites accessible by tractors and equipment
  • repeated tilling depletes soil seedbanks and carbohydrate reserves of perennial plants
  • nonselective; results in large areas of disturbed soil


  • plants that reproduce primarily by seed
  • mow during the flowering stage of target plants, before seed development and, ideally, when desired plants are dormant
  • repeated mowing may be required to prevent seed production
  • may induce plant to alter its form from upright to prostrate or by increasing shoots and flowerheads
  • nonselective


  • trees, vines, woody plants that do not resprout
  • timing can minimize resprouting; ideally, cut under drought conditions
  • labor intensive
  • grinding remaining stumps or painting them with herbicides may prevent resprouts
  • very selective


  • plants with taproots, root corms, rhizomes
  • labor intensive
  • minimal soil disturbance
  • very selective


  • trees and single-stemmed shrubs that do not resprout
  • labor intensive
  • results in standing dead trees and shrubs
  • very selective


  • small trees and shrubs that do not resprout from roots
  • land must be fairly flat and accessible to heavy equipment
  • nonselective


  • small annual plants
  • mulch early in the growing season
  • use in relatively small areas
  • somewhat selective, depending on mulch placement
  • use certified weed-free mulches

Soil solarization

  • winter annuals that germinate in cool conditions are most susceptible
  • small-seeded species
  • requires extended hot, sunny days
  • appropriate for defined areas with small populations
  • may alter soil properties
  • nonselective


  • plants with meager nutrient-storage capacity and/or short-lived seeds
  • extended periods of complete plant submersion required
  • nonselective


  • extensive mats of aquatic plants
  • short-term reduction of plant biomass
  • water body must be of sufficient width and depth to accommodate mechanical harvesters
  • floating plant fragments can spread to new areas
  • nonselective

Diver dredging

  • new, localized patches of aquatic plants
  • short-term, selective reduction of infestation
  • labor intensive

Erecting benthic barrier

  • small, localized areas of invasive aquatic plants
  • prevents establishment of native vegetation
  • labor intensive, initially
  • very effective but nonselective

Drawing down water levels

  • submerged plants; more effective on woody perennials than herbaceous perennials
  • in northern areas, winter drawdown may result in additional control by freezing plants and roots
  • requires dams or weirs to control water levels
  • selective based on timing

(adapted from AERF 2005, DiTomaso 2000, Hatcher and Melander 2003, Sheley et al. 1999, Sheley et al. 2001, Stapleton et al. 2000, Tu et al. 2001, Radosevich et al. 1997, and Venner 2006)