Spotted Knapweed

Spotted Knapweed is an invasive plant in North America, where it is estimated to occupy more than 7 million acres in the United States.

It's a pioneer species that is often found in recently disturbed sites or openings. Once it becomes established, it continues to spread into the surrounding habitat where it outcompetes native plants using these methods:
1. It has tap roots that suck up water faster than the root systems of other plants,
2. It spreads quickly because of high seed production,
3. Low palatability, which means that it is less likely to be chosen as food by herbivores, and
4. It is allelopathic and releases a toxin from its roots that stunts the growth of other plant species growing nearby.