More About...
...Purple Loosestrife

A wetland full of purple loosestrife might make you say, "Ooh." After all, these plants do grow beautiful purple flowers. But biologists look at purple loosestrife and say, "Boo, hoo!" They know too well the sad story of purple loosestrife and wetlands.

An unwelcome guest

Purple loosestrife is an alien species (see Special Feature for more on aliens). It was first planted in North American gardens about 150 years ago. Purple loosestrife soon escaped. It began growing in its favorite places: wetlands. There were no diseases or animals to hurt this alien invader. The other wetland plants couldn't stand in its way, either. Today, purple loosestrife grows in wetlands across much of the United States and Canada.

That's not the end of the story. Purple loosestrife doesn't just grow here and there in wetlands. It actually takes them over. Wherever purple loosestrife grows, it's the only plant around. It crowds out native grasses and other plants. They can't keep up with its growth. One healthy purple loosestrife plant may form up to three million seeds in a single year! Plus, new plants are able to grow from its stems and roots. When purple loosestrife replaces a natural mixture of wetland plants, the wetland suffers. Wetland animals cannot use purple loosestrife for food, shelter or nesting places.

Both Canada and the United States have government programs to help fight the spread of this plant. Conservation groups (such as Ducks Unlimited) are doing their part, too. While purple loosestrife can'Õt be wiped out completely, it can be controlled. One easy way to do this is called hand pulling. Flowering plants are pulled up by hand, roots and all. Each plant must be completely destroyed. Otherwise, it might spread more seeds or keep growing. Once the plants are pulled, they're burned or stuffed in garbage bags. Hand pulling is hard work, so it's only used on small populations of purple loosestrife. In other cases, purple loosestrife stems may be cut off or sprayed with poisonous chemicals.

Alien vs. alien

People have fought hard, but purple loosestrife is still winning the wetland war. A new weapon might soon change this. Biologists have decided to fight the flowering alien with another alien: insects from Europe. Biologists traveled to Europe, where purple loosestrife is native. They asked biologists there to help find insects that eat purple loosestrife or lay eggs on the plants. If biologists could be sure the insects wouldn't cause their own problems as aliens, they could bring them to North America. Then, they could turn the insects loose on purple loosestrife.

After years of study, the biologists chose a few different beetles to test in North America. These beetles go crazy for purple loosestrife. Adults and larva eat the leaves, flowers and roots. One kind of beetle lays its eggs in purple loosestrife flowers. As the eggs grow, they keep seeds from forming. All these activities make it harder for the plants to spread.

For a few years now, biologists have been releasing beetles into test areas in Canada and the United states. They started by setting up special tents near purple loosestrife patches. Inside each tent, biologists worked to raise thousands of beetles in a few short weeks. Then, the biologists carried the beetles outside and let them go. The insects went straight for the purple loosestrife plants!

Wherever biologists have released beetles, the insects have survived and laid eggs. In these areas, almost all loosestrife plants are damaged. Their leaves are filled with holes. Flower tops are chewed up or are missing altogether. No flowers means no seeds. And that means fewer purple loosestrife plants in the future. While wetlands may never be free of this flowering foreigner, many will be saved thanks to hardworking people and busy little beetles!

Conservation Corner

You can do your part to fight purple loosestrife.

• For example, many nurseries sell loosestrife plants. Don't buy them.

• You can hand pull patches of loosestrife that number fewer than 100 plants.

• For help with larger populations, contact a local provincial program in Canada or a state wildlife agency in the United States. Ask if they have volunteer programs that you can take part in.

• Be sure to spread the word about purple loosestrife, too.