Dodder twists itself around other plants to feed off of them.


Spreading Out If you wander through a large field of purple


loosestrife, you might admire its pretty flowers. Don’t be fooled by its beauty. T is plant is a danger to the wetlands where it grows. It grows in thick clumps and crowds out


plants that wildlife use for food, nesting, and hiding places. It chokes waterways. If you look below the ground, you’ll see the source of the trouble. It’s the roots of the purple loosestrife. Roots help anchor a plant. T ey also take in


water and minerals from the soil. Roots come in many shapes and sizes. A taproot is the main root. It has smaller roots growing out of it. In the loosestrife, the taproot is very thick.


As many as 50 smaller roots can sprout from it. T e roots store energy. So the plant stays healthy, even during seasons that are too hot or too dry. New taproots can grow from broken pieces of stem or roots. As the roots spread, they push farther into


the soil and form a dense mat underground. T ey crowd out other plants’ roots. Aboveground, the plant grows and grows.


Flowers shoot upward. Soon, each is packed with seeds. In one year, a single plant can make more than 2 million seeds. T e seeds are no bigger than a grain of


ground black pepper. Wind and water carry them. Animal fur or feathers can carry them, too. T e seeds can remain seeds for 20 years before growing into plants. With roots spreading out and new plants


taking root, the loosestrife quickly takes over. It thrives, while other plants die off .


14 NATIONAL GEOGRAPHIC EXPLORER


Purple loosestrife crowds out other plants.


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