How Land Managers Deal with Invasive Species

Land managers need to learn and understand the problems associated with invasive species. Second to loss of environment, invasive species are the greatest threat to native species and native ecosystems. Invasives will crowd out natives that wildlife depends on, along with changing hydrology, and even soil erosion.

Land management teams need to know Best Management Practices (BMP) to help with the eradication of invasive species. Basic procedures including: an inventory, a plan, and neighboring collaboration, will greatly increase the chances of success.

Taking a plant inventory of the site is imperative. Mapping the information collected is the next step. Knowing exactly where the populations of invasives or natives are helps with future monitoring.  This can also predict the possibility of invasion from alien species and allow for prevention.

Reading the landscape and knowing key indicator plants, allows the land manager to know what type of area they’re trying to protect. This knowledge, combined with the inventory and maps helps the land manager execute a plan.

One of the best defenses against invasives is early detection and prevention.  After conducting the inventory, data collected will relate the natives to the invasives. Knowing what/where natives do exist on the site helps with decisions in how to obliterate the invaders.

The plan should include an Integrated Weed Management (IWM) technique. A land manager must decide a control method to match the specific situation of the location. Control methods can include; physical/mechanical, chemical, biological, or cultural.  The choice of procedure should  be considered in with the available time, funding, workers/volunteers, quality of area, and land use goals.

Collaboration with neighboring land managers helps increase the chances of removal of invasives. This is through sharing of information, combined techniques of control, and the monitoring of invasive species.

Some of the invasive species challenging land managers today are:

  • Alliaria petiolata (garlic mustard)
  • Phragmites australis
  • Lythrum salicaria (purple loosestrife)
  • Phalaris arundinacea (reed canary grass)

Discussion of the preferred control methods currently used by land mangers are as follows:

Garlic mustard can effectively be controlled by either an early spring or fall burn of adequate intensity.  A combination of spring burning, hand-pulling (do you know this plant is delicious?!? Try it in salads or Italian sauces) and cutting increases the success rate. A spot application of 2% glyphosate, in spring or fall when natives are still dormant, can be done via spray (consider over-spray), or by a soaked glove. Biological control may be met in the form of one or more of four weevils. Scientists are currently testing the potential of one of these Ceutorhynchus species as a control method. Ineffective methods include low-intensity fires that leave plants unburned.




Phragmites australis is one of the hardest invasives to control. The only effective method that is agreed upon is application of an herbicide with cutting.  Rodeo must be cautiously applied as it is non-selective and will kill grasses and broadleaf alike. Application should be done after tasseling as that’s when the plant is supplying it’s rhizome with nutrients. Cutting would take place at this time also, if being utilized. Great success has been had with large infestations where the quality was otherwise low (less risk of quality loss), with aerial spraying of Rodeo. Covering a stand with black plastic attached to ground can work for smaller groupings. Biological control, at this time, is inconclusive/unusable as scientist have not found any organisms or viruses that damages Phragmites. Burning doesn’t reach the rhizomes of this species, but may be used to remove the cut litter.  Disking or pulling could effectively increase the population if proper removal of the rhizomes isn’t conducted.


Purple Loosestrife

Purple Loosestrife has historically been controlled with the herbicide glyphosate, sprayed in late August. Scientists have discovered leaf-eating beetles in the Galerucella family that are an effective biological control. Hylobius transversovittatus, a root-mining weevil has also shown promise as a control. Mowing, burning, or flooding has proven to be ineffective, as it seems to just distribute the seed.

Reed Canary Grass


Land managers have varying positions on dealing with reed canary grass. Some argue it’s value as regenerative to ditchbanks and the difficulty in identification of the native form from the invasive species. Because of these opinions, if possible, a small stand of reed canary grass should be allowed to stay. Burning in spring and fall, chemical controls, cutting, disking/tilling, altering hydrology, and plowing in combination (2 or more) can successfully remove this invasive. There are no known biological controls.

Land management teams should understand the issues surrounding invasive species including; Alliaria petiolata (garlic mustard), Phragmites australis,  Lythrum salicaria (purple loosestrife), and Phalaris arundinacea (reed canary grass). Implementing BMP procedures, along with an inventory, a plan, and including neighborhood collaboration will ensure superior success.

© Ilex Farrell ~ Midwestern Plant Girl

4 thoughts on “How Land Managers Deal with Invasive Species

  1. Pingback: The Hunt for Garlic Mustard for Tasty Meals! | Midwestern Plants

  2. Pingback: “Prairie Week” (September 18th – 24th) in Illinois | Midwestern Plants

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