Morning Marie,
Apologies that your report has gone so long without being claimed/addressed...until just recently, there was no one responsible for handling claims submitted to this site in Polk County, but that is no longer the case! Sounds like ownership issues might come into play in this one....is it technically right of way, individual ownership, etc. and on top of that, is there an HOA that would have any sort of power to cajole either the city or homeowners to treat the tansy? Either way, depending on the size of the infestation, there are several methods that can be used to control and potentially eradicate it...manual control via pulling/digging up plants before they have gone to flower, or if later in the growth cycle, before they have gone to seed is effective. Chemical control options with a variety of herbicides (Glyphosate, 2,4-D, Aminopyralid) exist and are most effective when treated in the spring (before flower) and fall. Biological controls in the forms of the Cinnabar Moth and Tansy Flea Beetle exist as well, but typically take ~6 years to make any sort of impact...Typically, a combination of all 3 control methods, sustained over several years, will help to make a measurable reduction in the size of an infestation!
- Jackson Morgan, Polk SWCD

Polk SWCD
July 27, 2020, 3:19 a.m.