I’ve been thinking a lot about invasive plants lately, because earlier this month I attended the Ecological Landscape Association’s winter conference where they were quite the hot topic, and I’m also preparing to write about them for one of my clients.
Let me preface by saying that at the ELA conference, which was fabulous, I attended all four of the permaculture talks that were offered by Dave Jacke and Jono Neiger. Dave is the primary author of a Edible Forest Gardens, a hefty and expensive 2-volume guide to “the ecology and design of home scale food forests” and the owner of an ecological design firm; Jono is the owner of a permaculture design and consultation firm.
Dave has an interesting perspective on invasive plants–frankly it takes cojones to get up in front of a crowd of green-minded, native-lovin’, invasive-hatin’ gardeners and landscapers and say some of the things that he did. But he had some good points, and I agree with him.
I prefer to use the term opportunist instead of invasive. Let me explain that. The word invasive, if you look up the word invade or invasion in the dictionary, it means a threat or attack. An army. If we call a plant or animal invasive, isn’t that anthropomorphizing? Do plants threaten or attack? [italics mine]
I understand, primarily because the piece of property I own is loaded with invasive plants and frankly is quite beautiful in the summer. The only mature tree on our property is a Norway maple that’s at least 50 years old. Most of it was already there when we bought the place, though I have previously confessed to planting English ivy and vinca minor (myrtle/periwinkle), before I knew much about invasive plants. We also have multiflora rose and Japanese barberry, and we used to have a giant Oriental bittersweet, which is the only invasive species that I’ve actually removed.
Plus, we are separated from a giant condo complex and old folks home by a large vacant lot that’s covered in Norway maples–they keep our yard very private. These plants are a major part of the architecture of our small (~7500 sf) lot. We aren’t rich, and since we can’t afford to replace mature trees and shrubs that serve an important purpose for us (privacy)–they’re not going anywhere.
Also, I don’t like it when I hear people talk about “trash birds” or “junk birds,” like house sparrows or starlings. I know that they’re hogs and they’re squeezing out bluebirds. I love bluebirds, OK? But as Hamlet said, “There’s a special providence in the fall of a sparrow.” And Hamlet was really quoting Jesus, who said “Are not two sparrows sold for a penny? Yet not one of them will fall to the ground apart from the will of your Father.” It’s not their fault that they’re sparrows, they’re not DOING anything. They just are what they are, doing what they do. It’s our fault they’re here anyway–they came to this continent on OUR ships.
Of course I realize that invasive species threaten the biodiversity of our ecosystem, but I have to think twice about spending so much money on removing invasive species and restoring native landscapes. Is it….wasteful? I don’t know. On a small property I’m aware of, it cost $20K to remove knotweed and restore native grasses and other plants. Maybe instead we should give it to say, India? I don’t know…it just gives me pause, that’s all.
Back to Dave:
If you understand succession ecology, you will understand that there’s no way a plant or animal alone can be responsible for the way it behaves. Invasion is only possible in the context of a certain kind of ecosystem situation. The first cause of succession is the availability of a site or niche. If there’s no site or niche available, no invasion can occur…. If invasion is not succession then what the hell is it? [italics mine]
The main thing is that the paradigm that we’re using to describe invasive species has many faulty aspects. The thinking is being muddled by framing the issues incorrectly. If we don’t see invasion as part of succession ecology then we are on the wrong track, folks. Because most plants that are considered invasive are disturbance adapted species.
I could go on and on about this. But I’ll skip to the solution. Dave has one:
The cropping principle is the corollary to competitive exclusion. When you have high competition and competitive exclusion occurring, the way to prevent competitive exclusion is by cropping the biggest competitor. If we can find uses for these plants..Kudzu grows very prolifically. It can be used for biodiesel, animal fodder, all kinds of food products, the list goes on. It’s an incredibly useful plant-that’s why it was brought here.
In other words, why can’t we figure out how to eat this stuff? Or use if for fuel, for cryin’ out loud?!
In the meantime, gardeners and others should not buy and plant them, and we should make our voices heard when we see them on sale in retail nurseries. (Frankly this is despicable. They KNOW BETTER.) And another thing that we can do is to stop the important of invasive species through better legislation. We as gardeners and nature lovers need to learn about these efforts and support them. I admit that I don’t know much about this, but I’m going to be learning about it soon for a client, and I’ll pass on what I learn.
Photo courtesy of Wikipedia.