Phragmites, how is it an invasive: Part 3

What classifies this Phragmites as invasive, why is this important, and what are the parameters for classifying an organism as invasive?

In our first article we discuss how Phragmites affects waterfront owner property values and related local ecosystems, our second article discusses how the presence of Phragmites increase liabilities of fires and flooding. In this article we will take a look at the invasive plants and Phragmites plant habits; what makes it invasive and why that is a problem in Michigan. In this article we will spotlight what makes this plant invasive and why knowing the difference is important.

An article written by Mary Bohling in 2013, Invasive Phragmites australis: What it is and why it is a problem?, shares technical information about this beautiful non-native plant and how it can grow from a seed, a cutting (any tiny piece), or a rhizome and how it thrives under a wide range of environmental conditions. The article further guides us to a valuable resource from Michigan Natural Features Inventory on this plant. That piece gives us a tool with details on how to identify the non-native Phragmites from the native variety. But some ask, “What makes a plant invasive?” And “How is that different than non-native invasive?”

In response to these questions, we first need to look at the definition of what makes any plant invasive. In my flower garden I think lawn grass is invasive. It gets in again and again even if I remove it. Why is it invasive? “Invasive” plants and animals have several characteristics in common. Yes, even some native ones. Ground covers for example, often fall into this same category. We want them to be so they will “cover the ground”. Unfortunately, left unchecked they can quickly overcome and invade where they are unwanted. Invasive organisms all have these similar characteristics:

  • They are tolerant of a wide range of environments and climates
  • They are not too fussy about soil or site conditions (wet to dry/shade to sun)
  • They are fast growing and mature to reproduction age quickly (start reproducing sooner)
  • They are prolific reproducers (make many eggs/seeds/babies)
  • In the case of plants, they can reproduce in more than on way (seed, cutting, rhizome)

Typically, this is an evolutionary adaption for organisms that have a lot of pressure for survival. Grass for example is a primary food source for many animals and insects. It is subjected to floods, droughts and fires. It has adapted to survive a multitude of conditions. For non-native species this is amplified in the fact that they are now in a new environment where there are few, if any restrictions or pressures for survival. Creating an explosion of their presence in the environment. This allows them to out compete native plants and animals often overtaking the local environment and crowding out the native plants and animals present.

Non-native invasive species are a global problem and are a major concern in Michigan. The Emerald ash borer is one. This non-native invasive insect has devastated forests in Michigan decimating a single valuable tree species – the Fraxinus species and cultivars (Ash trees). The spread of non-native invasive species has increased with global immigration and travel, global trade, and through the pet and landscaping industry. Sometimes, Non-native invasive organisms were introduced by accident; the emerald ash borer hitchhiked on Chinese wood pallets made from infested wood from China. Other times on purpose. Phragmites (the common reed), according to a Wikipedia article, has many uses ranging from water treatment to thatching for roofs, food and musical instruments. This plant was both accidently and intentionally introduced in North America.

Looking at Phragmites more closely we know that it fits the invasive species checklist. It is non-native, it is prolific, it matures faster than our native varieties; it propagates by seed, cutting, and rhizomes, thrives in a variety of site conditions and quickly becomes the dominant plant. It is also very hard to eradicate. Of course the best think you can do is to not to plant or spread this plant by making sure that we plant only native aquatic plant species near lakes, rivers and streams, and non-invasive plants only in our gardens.

For more information about invasive aquatic plants contact Beth Clawson, MSU Extension educator. To learn more about invasive organisms and invasive aquatic plants contact Michigan State University Extension Natural Resources educators who are working across Michigan to provide aquatic invasive species educational programming and assistance. You can contact an educator through MSU Extension’s “Find an Expert” search tool using the keywords “Natural Resources Water Quality.”

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