They've gotten that name because of their invasiveness, aggressiveness and the rate in which they spread.
Noxious weeds are difficult to control, and most are very adaptable.
They also can withstand a variety of harsh conditions, including climate extremes, drought and poor soils. There are approximately 1 million acres of noxious weeds in Colorado. Noxious weeds often displace native plants. Many native species have been forced out of their natural habitat. There are several noxious weeds in Colorado.