Hi, Carolyn. There are a number of species that the City of Portland feels it can address effectively. Unfortunately, because resources are limited, we can only work on species that we think we have a chance of controlling, and Canada thistle is just too widespread to be one of them. Many thanks, though, for keeping an eye on the environment, and feel free to reach me directly if you have questions or comments (mitch.bixby@bes.ci.portland.or.us).

-Mitch

Mitch Bixby
Oct. 12, 2009, 2:01 a.m.