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Purple Loosestrife

This is Roald Tweet on Rock Island.

If Hercules had been ordered to clean purple loosestrife out of the Upper Mississippi River as one of his 12 labors, that great hero would have turned in his timesheet and faded into oblivion.

As with so many plants brought from Europe by immigrants in the 19th century, purple loosestrife's sturdy beauty was our undoing. A patch of loosestrife's tall flower-filled stalks create a purple haze in the summer. Settlers prized it for its ease of growth. It was hardy—no North American wildlife eats it. Garden clubs planted it to beautify local swamps. Today, loosestrife grows wild in all states except Hawaii and Florida.

But nowhere does it grow more vigorously and viciously than along the Upper Mississippi lowlands, where each plant produces two million seeds a year. Near Winona, La Crosse, St. Paul, and everywhere, solid acres of loosestrife have crowded out native cattails, arrowhead, and bullrushes. Ducks and waterfowl can't build nests among the dense stalks. Submerged stems create such a tangle that fish can’t swim there. Acre after acre, purple loosestrife spreads.

By 1992, normally calm Minnesotans were worried that the states ten thousand lakes might all turn purple. Where Hercules feared to tread, the Minnesota Department of Natural Resources stepped in. They imported a small loosestrife—eating beetle, from Europe—Galerucella pusilla—at cost of $1.50 per beetle and set them working on the loosestrife near St. Paul and Winona. In three years, there were notable dents in the purple haze—replaced by dense stands of dead stalks. In five years, all ten acres near Winona were dead.

Today, the loosestrife plague seems over, leaving only a few unanswered questions. Will native species return, or will undesirable invasive weeds such as canary grass and garlic mustard take over? And what about the beetles, when the purple loosestrife is gone? What will they eat next?

The Minnesota Department of Natural Resources (and unnatural resources, too) is not worried. Somewhere in Europe, there must be a beetle-eating fish looking to emigrate to America.

Rock Island Lines is underwritten by the Illinois Humanities Council and Illinois Arts Council, a state agency, with additional funding from Humanities Iowa, the Iowa Arts Council, and Augustana College, Rock Island.

Beginning 1995, historian and folklorist Dr. Roald Tweet spun his stories of the Mississippi Valley to a devoted audience on WVIK. Dr. Tweet published three books as well as numerous literary articles and recorded segments of "Rock Island Lines." His inspiration was that "kidney-shaped limestone island plunked down in the middle of the Mississippi River," a logical site for a storyteller like Dr. Tweet.