They may be pretty but they are bad
What does it look like?
Opposite leaf arrangement
Stiff four sided stem
5-6 petals per flower
2-7 feet in height
Flowers are closely attached to stem
Flowers in late June to late December
Pinkish purple flowers
Make sure you don't confuse them with other common plants such as the fireweed, blue vervain and the dotted blazing star which have round stems instead of square stems.
Why are They bad?
Can reproduce thousands of seeds per plants
Large amounts choke other wetland plants
Displaces native plants
Wetlands are needed for other wildlife to survive
Difficult to control - 7 years to fully remove
How to get rid of it
Hand digging is the best way for small cases. Make sure that all the root tissue is removed. Dry out the plant material before disposal. For large areas, digging may not be the easiest way to get rid of them, remove the flower head before the seeds spread.