Invasive woody plants are especially problematic for our natural areas. Here are some examples of plants we used to have in our own yard.
Burning bush berries, just waiting to be eaten by birds
Like most people in the suburbs, we had a burning bush (Euonymus alatus). We got rid of it as soon as we discovered it was a non-native invasive plant.
This plant, more than any other (except perhaps buddleia) is the plant people refuse to believe is invasive. It's hard to believe, but they sometimes even become quite hostile when I suggest that it causes problems.
They say that it doesn't travel around their yard. They don't realize that birds eat the berries and deposit them in the woodlands through their droppings.
Burning bushes invading the woods; "invisible" because they lack their characteristic red foliage
They say they don't see it invading woodlands. Perhaps it's because in shady woodlands, it may not always develop its characteristic red color.
This Japanese barberry seedling appeared in our yard almost ten years after we removed our barberries. How it got there I don't know. Did the seeds from that plant finally germinate? Or did seeds from another barberry in the neighborhood drift to my yard?
I suspect it's from seed that germinated from the seedbank of our own barberries from long ago. It has the same chartreuse color.
It's scary to think that our old plant, pulled out so long ago, can still be spreading.
Barberries invading our local nature center
It's very sad to see how much land barberries can overtake. This land in our local nature center could otherwise be supporting the kinds of shrubs and other native plants that are so important to our native wildlife.
It seems to be difficult for people to understand that their own landscape plants could be the source of an infestation like this. After all, they don't see their plants picking up and moving. But also what they don't see are the birds eating the berries and pooping out the seeds, along with its own little packet of fertilizer (i.e. the bird poop).
Buddleia (aka butterfly bush)
Butterfly bush (Buddleia) is another one of those plants that people refuse to believe causes problems.
Of course, it doesn't help that almost any article on creating butterfly gardens includes this plant. Why not? If you're creating a butterfly garden so you can sit back and enjoy watching butterflies flocking around your buddleia, I guess it makes sense.
If, on the other hand, you're interested in what's best for the butterflies and for preserving that enjoyment for our grandchildren and beyond, it makes no sense whatsoever. Butterflies need larval host plants for their caterpillars. Nectar plants are easy to provide; there's no need for this plant.
Here are some alternatives to buddleia and the reasons we eradicated our buddleias long ago.
Multiflora rose (Rosa multiflora) is another plant that's widespread in our local nature center and in many other places. The difference between multiflora rose and the Japanese barberry that's also invading these woods is that the multiflora rose WAS PLANTED ON PURPOSE—hard to believe, but at the time, people thought they were doing a good thing.
It's also hard to believe that long ago I found a seedling of a plant that—lo and behold!—produced little white roses.
I coddled this free rosebush for a few years until I finally understood what it was. Then, coddling it no more, I ripped it out by its little roots!
A large Japanese honeysuckle (Lonicera japonica) was in our yard when we moved in. This is another plant that I coddled for a number of years, thinking it was a "free" flowering shrub. When we learned about invasive plants, we got rid of it.
Fortunately, we never planted this one in our yard, but this photo of Japanese knotweed (Polygonum cuspidatum) was taken along a road not very far from our house (in connection with an article I wrote that appeared in Woodlands and Prairies magazine).
It could have been taken almost anywhere in CNY, though. It's everywhere.
Amazingly, some people think it's attractive (we actually saw it on a supposed "habitat garden" tour in another city!) Or if they don't think it's attractive, they consider it one of those "weedy native plants" we have to guard against.