Frequently Asked Questions

How can I get my neighbor to control their invasive weeds?

It is important to work with your neighbors, when controlling invasive weeds.  Invasive weeds ignore property boundaries and routinely jump from one property to the next.  Many landowners don’t discuss this issue with there neighbors to avoid conflict.  As a result in many cases, property lines are under-managed because of concerns about encroachment on neighboring properties.  In these cases we can help!  The WeedWise program is non-regulatory and we have staff available to help landowners develop a plan for controlling their invasive weeds.  We recommend that landowners start by initiating a conversations with their neighbors by telling them about the resources available to them through the WeedWise program.

If discussions with neighboring landowners fail to yield results, it is important for landowners to know what additional actions are available.  There is no county-level regulatory authority  empowered to enforce noxious weed rules and regulations.  While there are Oregon noxious weeds laws, enforcement of these laws by the Oregon Department of Agriculture Noxious Weed Program is limited to high priority class A noxious weeds.

Many of our local municipalities have nuisance ordinances that require weeds and other noxious vegetation to be removed or kept below a certain height to prevent seeding. The specific ordinances differ widely from city to city.  For questions about local nuisance ordinances and enforcement, contact your local code enforcement for specific information.

Outside of municipalities, there is no enforcement and it is recommended that neighbors work together to control invasive weeds across property boundaries.  If neighborly relations sour, landowners are encouraged to contact Dispute Resolution Services for assistance.

How do I manage tansy ragwort growing on my property?

Tansy ragwort is a common invasive weed in Clackamas county, and it poses a real threat to livestock and to hay producers.  We recommend that landowners actively control tansy, especially in areas near grazing livestock or active hay production.  We have developed a Tansy ragwort Best Management Practices document to help guide landowners in their management.

We recently received a letter and and permission form in the mail. What do we need to do?

When we are working to detect and control priority invasive weeds, the WeedWise program begins by reaching out to potentially affected landowners.  Prior to initiating a project we send a landowner packet that includes a letter explaining the project and efforts underway in your area as well as supplementary information that may be of interest to landowners.  The packet also includes a two copies of our Permission to Survey and Treat form, as well as a stamped return envelope.  We require all landowners that are interested in participating in the program to sign one of the permissions in the supplied envelope and keep one copy of the permission for their records.

The Permission to Survey and Treat form also asks for contact information.  This information will be used only to notify you when activities are planned for your property, so please provide accurate contact information.

Why is the tansy ragwort so bad this year?

Tansy ragwort has a long history of active management in Clackamas County.  Since the 1940s landowners have been encouraged to actively control tansy ragwort to protect livestock for accidental poisoning.   In the 196os and 1970s several insect biological control agents were released to combat tansy ragwort.  These insects have been very successful in keeping tansy ragwort populations at much lower rates. Unfortunately, in seasons with very prolonged and wet weather conditions in spring, the effectiveness of these biological control agents is diminished.  As such, we experience a temporary resurgence of tansy ragwort.  In these years, we strongly encourage landowners to take a much more active role in controlling the tansy ragwort to help keep populations in check. To learn more about the history of tansy ragwort in our please check our web post Tansy Ragwort Poisons Livestock and Neighborly Relationships.


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