Once upon a time, we actively tore out “invasive” plants. We participated as volunteers with our local soil water conservation district and with our parks department. We thought we were doing a good thing….and maybe we were….sometimes.
But after a few years of helping to rid Minnesota of invasive plants, we started to realize that maybe we were wrong. It all started while helping the parks department gather native prairie seeds and listening to the manager tell the story of that particular zone of Minnesota. It was historically, “big woods” but the parks department wanted to maintain a prairie ecosystem (for educational and seed selling purposes.)
Every other year they burned the prairie to keep out the encroaching shrubs. That was when our opinion changed.
The general attitude is that “natural is good” except that they don’t always follow what is “natural.” For example, the prairie situation above. Naturally, a prairie evolves into a shrub land and then into a forest. Then the forest burns down and a prairie starts in the ash. By perpetually keeping an area as prairie, we are defying the natural order.
Does this sound hypocritical? We are growing 12 acres of native prairie on our farm, and we love prairies! We are not saying the park department is wrong in keeping a prairie in the big woods – we are saying it’s not natural. It’s not “native” if you will. And that’s okay.
There are benefits to keeping and protecting a particular ecosystem. Prairies are endangered; having been turned into cropland centuries ago. As humans, we need to innovate, create, and survive. We get to decide!
Croplands, prairies, forests, and wetlands are all important. Native plants are important.
But what about non-native plants?
This is where it gets messy. Some people will tell you that all non-natives are bad and need to go. No questions asked. But that isn’t right.
Let’s start at the most obvious problem with this mindset. Almost every US citizen is non-native to this land, and by the definition of displacing the native people, invasive to boot. The history is sad, but in the end we are all here now and diversity is good.
Maybe its the same with plants and animals.
Honey bees are not native. Apple trees are not native. Chickens are not native. Almonds are not native. Wheat is not native. Strawberries (as we know them) are a hybrid of native and non-native species (this is actually an exciting story of plant genetics across three continents and worth a read…look it up.) This list could go on for a long time.
The point is there are a lot of non-native plants and animals that are beneficial and welcome in our life. I think most people can agree in this area. But not all non-natives become “invasive.”
What does it mean to be invasive? According to the USDA forest service:
An “invasive species” is defined as a species that is: Non-native (or alien) to the ecosystem under consideration; and, Whose introduction causes or is likely to cause economic or environmental harm or harm to human health.
Buckthorn, purple loosestrife, birdsfoot trefoil, reed canary grass, crown vetch, black locust, autumn olive, russian olive, siberian elm, garlic mustard, multiflora rose, various clovers, dandelion… this list could also go on and on.
So many of these plants get listed as invasive because they grow well under most circumstances. They are often pioneer species that show up “to repair” an area that has been badly abused or disturbed.
Sometimes they take over.
So what? Maybe it’s okay for a land to evolve? Maybe there are benefits to invasives moving in? Maybe they will only be there a short while as the land heals and natives can move back in? Maybe it will result in a more diverse and stable ecosystem for the long term? None of this is black and white.
When we purchased our farm, we went through and cut out every single buckthorn tree. Every single one of them grew back within a year. That’s amazing. We are growing in almost pure sand in one of the coldest habitats on Earth. And those trees came back with a vengeance in less than a year.
You know what – God bless ’em. Their wood is hard and burns hot, so they are an almost never ending supply of firewood. With buckthorn around, we never have to cut down a live “native” tree for firewood. We can also use the branches for trellises and crafts. The berries are poisonous and taste like death (don’t ask how we know and do not try them yourself!) Even better – they provide nectar and pollen for bees. They are not all gloom and doom.
Can they overrun a forest? Sort of. Maybe. Yes. We have traveled all over the country and all over the parks and trails of Minnesota. We see buckthorn all the time. It usually doesn’t gain a big foothold in our forests unless something else has happened. When other trees die because of big equipment, herbicide, new housing developments, animal damage – then invasives move in.
If they were in the middle of our prairie, I would use an uprooter weed wrench and pull them out while they are young. Or cut them down and paint the stem with an herbicide. The key is management.
But what about the areas that can’t be aggressively managed? So what? Maybe it was ready to evolve? If there are areas that must be maintained, then they have to be managed. This is what our conservation and parks departments do. Sometimes it makes perfect sense – sometimes it doesn’t. Sometimes an ecosystem is strong enough that invasives can not and do not gain a foot hold. That’s good too!
I recently read that the wildfires in California could be better contained if the parks department did not go in with roundup to take out the stands of Aspen that colonize a newly burned site. Makes sense. Aspens are soft and “wet.” They don’t burn like a pine tree. They also move in and spread aggressively. They are also native. But they want to maintain a pure stand of coniferous trees, and so the fires rage on….
There are many more examples. Since we work a lot in the prairie space, there are so many complaints about birdsfoot trefoil, sweet clover, and hairy vetch. All of those plants are not only good pollinator plants, but they also improve the soil by nitrogen fixing. Beyond that, they are excellent fodder plants for livestock. But they aren’t native, and they grow well without chemical assistance, so they are battled like mad to keep out of lawns and prairies. Truth be told, in a really healthy prairie or lawn, birdsfoot trefoil and hairy vetch would be shaded or crowded out. Sweet clover may also slowly phase out (ask me in a few years.) A prairie is never stagnant, and neither is nature. Plants move in and out all the time.
Two that bother us the most are black locust and autumn olive. These plants are on almost every state list (not Minnesota yet, crossing fingers.) Both of these plants are extremely useful. The black locust grows quickly, fixes nitrogen, has edible flowers, provides ample nectar for insects, and produces hard rot-resistant wood.
The autumn olive is amazing. It also fixes nitrogen, has prolific flowers for pollinators, and makes tasty sweet berries full of lycopene.
We could go on and on about all the benefits of some of these plants. It’s all situational. The thing is – we can’t just throw out every plant that might be invasive. There are serious benefits, especially if we are going to go into the future with more than 7.5billion people. We have to rethink how we manage this Earth – our farming practices, our consumption habits, our use of the soil. Invasives might be the key to saving us all.
Besides, native doesn’t mean sacred. Poison ivy is native. Deer flies, horseflies, blister beetles, and mosquitoes are also native. Lots to think about.
Here are some articles that explore the native vs exotic topic further: