(Editor's Note: This article was originally published on June 26, 2010. It is being repeated this week as we continue our invasive species contest. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)

Aggressively colonizing, exotic plants (think kudzu) are shockingly easy to find almost anywhere that humans destabilize an ecosystem. Do you know about tamarisk or watermilfoil or multiflora rose? Those are just a few of the many and varied invasives that plague public lands across the United States. For a decade or so, Weed Warrior invasive plant control programs have been springing up across the U.S. and Canada, too. Weed Warriors is a catchy name used by dozens of programs that enlist local volunteers to battle invasive plants. (Australia has a national student Weed Warrior program, complete with website.)

Park and public land managers are harnessing the energy of hundreds of volunteers to wage war against non native invasive plants. I was one such energetic volunteer several years ago. A local park offered Weed Warrior training and would reward volunteers with an annual pass. Our group first spent an hour or so discussing the species of concern for that specific location. We were shown color photos and given handouts with identification tips. Then we went into the field, literally, to survey areas we were to work on. Removal techniques were part of the training. It's good to know for example, that a patch of mile-a-minute vine at a certain growth stage can be lifted and rolled up almost like a sheet. That makes the work more efficient as the worker prevents a whole year's worth of potential seeding in the process. After the training, we were ready to unleash our horror on the invasives (at least, as much horror as a half dozen "weekend warrior" type amateur naturalists can unleash.) In our first session we cleared a large area of mile-a-minute vine, freeing native grasses, wildflowers, and berry bushes.

While I sure appreciated my "free" park pass, I discovered an unforeseen disadvantage to my Warrior training. I don't mean the sweat and scratches of several hours of weed pulling and cutting. The real downside was my newfound skill at recognizing the same invasive plants in every other park I hiked in. I didn't even need a nature walk to find non-native invasives. My own yard was an unwitting host to a few intruders. I spotted them behind shopping centers, and next to the ball field and on roadsides. I was getting an itchy pruner finger, thinking of the more interesting and valuable plants I might be helping if only I'd free them of the tyranny of tree of heaven or Oriental bittersweet vines.

There are very good reasons for NOT beginning a vigilante-style campaign against non-native plants wherever they crop up. You might think any park ranger would welcome all efforts at invasive management. However, some areas may be under study in anticipation of an upcoming Weed Warrior program. Imagine getting all psyched up for a weeding party, (or having spent time preparing your volunteers), and finding the weeds gone! One park I read about planned to employ two different control methods in order to study them for comparitive effectiveness. That wouldn't work so well if you had interlopers doing uncounted hours of work. And all Weed Warriors may not be created equal. There's a danger of an amateur range rover going after the wrong plant; is that really a Canada thistle, or a bull thistle? Is it one of the other 80 or so plants in the Cirsium (thistle) genus found somewhere in the United States? For these reasons and others, don't spontaneously battle invasive plants on public land, or land you don't legally own. Seek out and work with whoever is charged with supervision and maintenance of the area in question.

Like any volunteer program, Weed Warriors brings together individuals who have personal interest in a "cause." This cause might be decribed as "helping preserve diverse ecosystems on public land." Not all parks can offer enticements with cash value. You often bring your own gloves and tools, and you might be lucky if the ranger can spring for sodas for the team. Weed Warrior events can offer a good practice session in wild plant identification and the chance to mingle with other people of similar interests. A few programs mix in some fun, like the annual Garlic Mustard Challenge event in the Patapsco Valley in Maryland. A poster contest, awards for most pounds of mustard pulled, and a cooking contest (this weed is edible) add to the party spirit of the day.

Non-native, invasive plants are here to stay, and they threaten the diverse natural environment many people value. If you're willing to fight, you should, and probably can, find a Weed Warriors program in your home state.

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More information about more invasives, and not just plants, is on the website Invasives.org - This link takes you to the home page of a complete informative site.