Land Plants - invasive

Purple Loosestrife (Lythrum salicaria) on Aug 28, 2009

Submitter does not have a specimen

Description of specimen

Purple loosestrife appears to be widespread in Oaks Bottom. I did not go down to see the plants up close but I know the purple haze and it likes wetlands. Why isn't this plant on the list of invasive wetland species? Maybe the common name is swamp stonecrop?


Greetings, Stan. The common name of swamp stonecrop refers to a New Zealand & Australian native Crassula helmsii, which is not known here in the states. But, as you noted, purple loosestrife (Lythrum salicaria) is widespread there at Oaks Bottom. Portland Parks and Recreation Bureau is aware of the situation and has been doing releases of two types of weevils for the last few years. Biocontrol does take a while to really have a notable effect, so until the populations of these insects really take hold, there's still going to be blooms of loosestrife.

Purple loosestrife is in fact a designated Class B noxious weed here in Oregon (unfortunately it's widespread enough that it's not listed as a Class A weed).

Thanks for taking the time to submit a report and let me know if you have further questions.

Vanessa Howard Morgan
Portland State University - Center for Lakes and Reservoirs

Vanessa Howard Morgan
Aug. 28, 2009, 9:53 a.m.