Avoid Planting Invasive Species

Invasive species are species that are not native to an area, but once introduced to an area can spread rapidly and crowd out other species. Not all non-native species are invasive, but some are and those species can cause significant ecological damage. Invasive species also have an economic impact as local, state, and federal agencies spend millions of dollars each year to manage invasive species on public lands.

Many pollinators are attracted to autumn olive (Elaeagnus umbellata) flowers and songbirds will eat the berries. However, it is highly invasive and causes significant ecological damage by outcompeting other plants. Photo credit: Erin Nikitchyuk, cc-by-sa 4.0 

Unfortunately, many invasive species can still be purchased and some are even promoted as good for pollinators or certain wildlife species. However, scientific studies comparing stands of invasive species with similar areas containing more natural vegetation have repeatedly found less plant and wildlife diversity in the stands containing more invasive species. Ohio recently passed a law making it illegal to sell 38 species of plants known to be invasive in the state, but most states don’t have such laws.

To avoid planting invasive species, do your research before planting a new species. Don’t take lists of “good plants for ________” at face value because they may only be focusing on one piece of the puzzle, without recognizing the larger picture. For example, butterflies may feed on nectar produced by an invasive plant’s flowers, but their caterpillars may not be able to eat the vegetation. This can be a problem because the invasive plants crowd out other species. The invasive species, therefore, could be drawing the adults to an area where there are no plants that they can lay their eggs on which will provide their babies with food. Another example is that songbirds may eat the berries from an invasive species and inadvertently spread the seeds through their dropping, but may not be able to find adequate shelter or may experience higher nest predation in the stand of invasive species that grows from those seeds. In both these cases, the overall impact of the invasive species is negative.

Also, plants may be invasive in one state, but not another where the ecological conditions are different. Most states keep lists of invasive plant species. If you aren’t familiar with a plant, do a quick check of your state’s invasive species list to make sure planting it isn’t going to contribute to a larger ecological problem. In Kentucky, the invasive species list is developed and maintained by the Kentucky Exotic Plant Pest Council. In addition to maintaining the invasive plant list for the state, they also offer suggestions of native alternatives. The good news is that there are always other alternatives, either native or non-native, that are just as good for pollinators and wildlife, but don’t cause the ecological damage of invasive species.

This article was part of Shannon’s original Kentucky Pollinators and Backyard Wildlife blog which evolved into the blog for Backyard Ecology.

Backyard Ecology: Exploring Nature in Your Backyard
Nature isn’t just “out there.” It’s all around us, including right outside our doors. Hi, my name is Shannon Trimboli, and I am the host of Backyard Ecology. I live in southcentral Kentucky and am a wildlife biologist, educator, author, beekeeper, and owner of a nursery specializing in plants for pollinators and wildlife conservation. I invite you to join me as we ignite our curiosity and natural wonder, explore our yards and communities, and improve our local pollinator and wildlife habitat. Learn more or subscribe to my email list at www.backyardecology.net.

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