Invasive Species Control

Invasive plant species are a rapidly increasing threat to the natural ecosystems of Iowa. Combat and control methods for some of these species can be exhausting, but you can help.


This quick growing and highly invasive shrub hinders the health and succession of our natural areas by crowding out native plant species on our forest floor. The dense shade layer created by the overcrowding of this shrub’s canopy can destroy an ecosystem by altering the flow and capacity of its nutrients and moisture.


To limit the growth and spread of this species, Hardin County Conservation staff uses several control methods ranging from mechanical, biological, and chemical:

  • Cut stump treatment:
    • Cutting the shrub at the base would be an example of mechanical control, using an    herbicide application at the cut surface of the stump would be an example of chemical    control, inhibiting further growth or re-sprout of the plant.
  • Prescribed fire:
    • This treatment is not a complete control method for this species, but is a tool used regularly across most of our properties and often sets back smaller shrubs. Re-sprout is common, and must be treated with a form of chemical control.

Wild Parsnip:

Pastinaca sativa is an invasive species commonly known as wild parsnip, and is a member of the carrot family. This plant is easily recognizable by its bright yellow and umbel shaped flower. The leaves and stem are distinguishing factors when comparing to plants with similar flowers such as goldenrod or golden alexander. Wild parsnip has leaves that are coarsely toothed and compound, with grooved hollow stems.



This plant is a biennial that only spreads by seed. This means that the plant has a two year life cycle, and flowers during its second year. The only means of reproduction for this invasive is through reaching its blossoming/seed production stage.

  • Cutting/mowing
    • Cutting this plant at the base during its blossoming stage will eliminate the chance for seed production on that plant. Stopping it in its tracks.
    • Missing just one flower can result in hundreds of new seeds
    • A hand-use cutting tool can be used for small areas with few plants, a mower or brush blade can be used to eliminate plants crowding a large area.
    • Be sure to wear protective sleeves on your arms and legs, as well as gloves, to avoid skin contact with this plant.