Quick Guide on Invasive Plant Species

What is an invasive species?

Put simply, an invasive species is anything that exists in an region to where it is not indigenous.  This usually happens when an organism (in this case, a plant) is carried from one part of the world to another.  The new organism then finds itself in a place where it has no natural enemies, and its particular characteristics make it a bit of a bully in its new home (thus earning it the title of ‘invasive’).  This happens a lot with animals, but for this article we are just going to focus on a few types of invasive plants.

 Japanese barberry (Berberis thunbergii)

jap bar1

jap bar2 Holiday Inn… but for ticks.

Where did it come from?

As its name suggests, it was originally brought over from Japan because it looks pretty, which is fine for the most part.  The problem comes when you realize that this particular plant is not eaten by local deer, and resistant to local plant diseases that would otherwise keep it in check. It has also been extremely good at beating out native species for nutrients which results in the death of the local species.  These things are also luxury condos for ticks. This little guy can also raise the Ph of the soil where it grows, which will make it super difficult for anything growing around it to thrive.  DO NOT PLANT THIS IN YOUR GARDEN.

How to identify:

Knowledgable gardeners can identify this by the flowers, but amateurs might do better to check the leaves: small, oval shaped, smooth and untoothed.  They are usually green, blueish-green to dark red or purple.

How to get rid of it:

No special tricks here, you can just dig it out and toss it in the garbage.  Just make sure to get all the roots and you are good.  Be sure to test the Ph after it’s gone to see if you need to adjust the soil back to neutral.

Japanese Knotweed or Mexican Bamboo


NOT actually Bamboo.

Where did it come from?

Also originating in Japan, this was brought over sometime in the late 1800’s and used as erosion control due to its rapid growth and overall resilience.  Since then, it has spread all throughout the US and has become one of the world’s most invasive species.

How to identify:

Its name is misleading: it’s not actually bamboo, but it looks a lot like bamboo, so much so that people have started calling it American Bamboo.  Other names include: fleeceflower, Himalayan fleece vine, monkeyweed, monkey fungus, Hancock’s curse, elephant ears, pea shooters, donkey rhubarb…

How to get rid of it:

If you have a lot of this stuff, the most effective thing you can do it call someone with a backhoe.  Seriously.  Knotweed has a large underground network of roots and it very quickly crows out anything around it.  If you want it gone, you will need to dig it out.  All of it.  It’s going to be expensive, but its the best way to make sure its gone. If you just have a little, you actually have a lot and it’s trying to trick you.  You just can’t see it.  Start digging.

Burning Bush


Showing off its fall coloring.

Where did it come from?

Again, brought over from Japan for its brightly colored berries and bold fall hues from which it gets it’s name.  This is actually illegal to sell in parts of the northeastern United States, including Maine, New Hampshire and Massachusetts.

How to identify:

It turns bright red in the fall, but to identify it during the rest of the year look at the branches.  up close, you will likely see four corky ‘wings’ on each branch that go along the length of the branch.  If you see those, you have a winner.

How to get rid of it:

This one is also nice and simple: Dig it up and throw it into the garbage.  Don’t forget the roots, and don’t toss it into the woods where it could drop any seeds.

Asiatic bittersweet


Where did it come from?

A creeping vine native to Eastern Asia, it was brought into the United States because it looked pretty.  Now that its here, it manages to get itself just about everywhere and can slowly strangle an entire tree.  This means that it can easily overrun and choke out your own little garden if you let it go unchecked.

How to identify:

The vines themselves are thin and spindly, and have silver to reddish-brown bark, usually between 1-4cm in diameter.  The leaves are round and glossy, 2–12 cm long, have toothed margins and grow in alternate patterns along the vines.  Will grow in a thicket when its by itself, or can encircle the trunk of a host tree or entangle itself in the branches of bushes and shrubs.

How to get rid of it:

Once you see it, start yanking it out.  Once you find where its laid roots, get as much of it as you can.  If you aren’t certain that you got all of it, keep an eye out for regrowth and yank that too.


Also worth reading:  Giant Hogweed


Happy Gardening!

~The Greencare Team