Non-Native vs Invasive Plants

By: Andrew Obloy

Our native plants are amazing.  They are here for a reason, and we should use them as much as we can in our own landscapes. That being said, not all non-natives should get a bad rap. For many, the word invasive feels synonymous with non-native. I will always encourage the use of native plants in your own garden, but I don’t think we should look at all non-natives as evil invasive species.

“Kudzu on a Bridge” by Suzie T is licensed with CC BY 2.0.

An invasive species is one that is introduced to an ecosystem where it outcompetes the native species and essentially takes over, dwindling the native species, significantly altering the native ecosystems. Even just in our small part of the world, there are many invasive plant species you see everyday and may not even realize. Kudzu is a vine that was introduced to the United States in the late 1800s as an ornamental vine used to shade porches, similar to how many people use Wisteria today. Now you can see kudzu overtaking and smothering trees just about anywhere in your native environment. Another very aggressive invasive plant is Japanese stilt-grass. This highly invasive plant species spreads very quickly and will outcompete native plant species and reduce wildlife habitat. These two plants arrived into our native ecosystems under different circumstances but are both causing harm to our native flora and fauna. Care should always be taken with non-native species of any kind, but that doesn’t mean they are all invasive and will cause this kind of damage.

“Boxwood fantasy” by Stewart Holmes is licensed with CC BY 2.0.

When it comes to finding non-native plants that are not invasive it is not so cut and dry. Non-native boxwood are one of the most common plants found in our Mid-Atlantic gardens. You can fill your entire landscape with them and never see a new one that you didn’t choose to put there. The reason for this is that Boxwood do not self-propagate well. It takes a bit of human intervention to create new boxwood, so its hard to see how this plant is going to outcompete our native species on its own. It can get even more confusing, when you have plants that are able to reproduce more easily on their own or with help from wildlife or weather, but still can’t grow and reproduce at a fast enough rate to outcompete what is growing naturally around it. This could include something like Japanese hollies, their seeds can be spread by wildlife, but they take too long to grow and reproduce to cause much of a threat to what is growing naturally.

“Crocosmia by garden pond” by is licensed with CC BY 2.0

Herbaceous plants can be more difficult to define. Many may have some hybrids that are invasive in some parts of the world but not here. Crocosmia is a plant native to Africa but is now grown all over the world.  Only a few hybrids are invasive, but none are invasive to our part of the world. You should never introduce a highly invasive plant to your own garden, but many non-native plants can be easily kept in check with the right care and maintenance.

Native plants and ecosystems are a gift to us and should be treated as such. That doesn’t mean that all non-native plants should be considered invasive or evil. If we take care in our selection and maintenance of plants, we can have the best of both worlds.

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