Erect perennial, with a long spike of pink, showy flowers. Leaves opposite, arranged in whorls.

Invasive, non-native, noxious weed.

Is native to wetlands in Europe, it's to wetlands that it poses a risk in North America.

In our city, is invading wetlands via storm sewer outlets, evidence of seed washed there from city gardens. If you're growing this in a North American garden, shame on you. It's likely well behaved in your garden, but it's the stream or marsh within a kilometre of your garden where it will spread.

Height to 100 cm.

Took the above photos in late July along a stream in the Wood Meadows subdivision in Regina, SK, about 100 metres away from a selfish idiot growing this in their garden.