Invasive Species Resources

Weed Treatment Calendar

The Weed Maintenance Calendar contains guidance on how and when to control invasive plants within the 4-County region.

Airtable is available for download as a CSV file. (Updated 2021)

This treatment calendar is based on data compiled from the 4-County CWMA partners. The tool reflects the prevailing opinion for managing invasive weeds in common situations. While the calendar might be useful to the general public, please note that it is intended for professionals. 

As with all invasive species management, land managers need to analyze each infestation on a case-by-case basis. The recommendations outlined in the calendar are not a one size fits all approach, but rather a general overview of various treatment types and species.

The 4-County Technical & Scientific Review Committee reviews this resource biennially and makes changes as necessary. Please feel free to join the conversation and watch for future updates.

Download a printable Integrated Weed Maintenance Calendar (updated 2020).

If you have any suggestions for the calendar, please contact our Technical & Scientific Review Committee Chair(s):

Justin Cooley
Clackamas Soil and Water Conservation District
Technical and Scientific Review Committee Chair
Email Justin Cooley