The Prickly Thistle: A July 2018 WeedWise update

Welcome to the July edition of the WeedWise newsletter, known as the Prickly Thistle! This is our opportunity to share with you just some of the great activities underway here at the WeedWise program!

False Alarms and Why We Love Them!

Kudzu infestation in the Southeastern United States

Here at the WeedWise Program, we receive a wide variety of calls and emails related to invasive weeds. July, in particular, tends to generate a large number of landowner inquiries. The vast majority of these landowner contacts are related to questions about many of our most common weeds. Weeds like tansy ragwort, Himalayan blackberry, Scotch broom, and English ivy are widespread and have a profound impact on local landowners. Therefore, it is no surprise that they are our most commonly voiced concern.

Every once in a while we receive a report about a weed that we don’t expect. These rare and unexpected calls peak our interest because they represent a potential opportunity to exercise a weed management strategy known as Early Detection and Rapid Response (EDRR). This strategy focuses on first detecting new invasive weeds and then taking immediate action to eliminate the threat before it has a chance to become the next Himalayan blackberry or Scotch broom.

The response to these new invasives is not unlike a firefighter’s response to an emergency call. Much like fighting a fire, we begin by assessing the threat, establishing a containment perimeter, and then responding quickly to extinguish the threat. Instead of fighting a fiery blaze, we are battling a biological wildfire of weeds.

The big complication in dealing with invasive weeds is that it is not always clear to folks what poses a threat. The Clackamas Weed List currently includes 220 invasive plants. This diversity of invasive weeds can create much confusion. Imagine someone calling 911 to report a fire, when they’ve never seen a fire before! As a result, we occasionally receive false alarms about new invasive weeds. Just in the last month, we have received false reports of kudzu, rush skeletonweed, and garlic mustard.

These false alarms undoubtedly pull us away from other important tasks, but believe it or not, we are happy to have them! We welcome these alerts for three reasons:

  1. These reports demonstrate people are concerned about the threat of invasive weeds to Clackamas County. More than that they are also willing to take action! For this we are grateful. Complacency is our great enemy when it comes to invasive weeds.
  2. A false report means that no threat was found! This is much more desirable when compared to the sinking feeling we get whenever we find a new infestation of a high priority invasive weed. With a false report, our time and resources can instead be applied to address existing concerns.
  3. If just 1 in 100 reports results in the positive early detection and rapid response of a new invasive weed, and we are able to suppress the impact of that we, then we know our efforts have been successful.

So many thanks to everyone that has ever taken the time to report a new observation. If you don’t feel confident identifying invasive weeds, take some time to familiarize yourself with the invasive weeds threatening our area. One great resource for learning new EDRR targets for the state is the Western US Invasive Plant EDRR Weed Guide. If you find a new priority weed, report your finding to the Oregon Invasives Hotline or contact the WeedWise program today!

Please enjoy the WeedWise program’s July edition of the Prickly Thistle!

Samuel Leininger

WeedWise Program Manager

We Are Hiring!

Do you have an interest in invasive plants? Do you have the technical and organizational skills to manage complex projects? If you answered yes to both of these questions, then we are looking for you! The WeedWise program is currently accepting applications for a full-time WeedWise program specialist that will also serve as the shared coordinator for both the 4-County and Columbia Gorge Cooperative Weed Management Areas (CWMA).

This important and highly visible position interacts with land managers from across the region. So if you want to help to shape weed management priorities across the region, Submit your resume, cover letter, and application today!

Learn more about how to apply for this opportunity on the official WeedWise Specialist and CWMA Coordinator Position Announcement.

July Weed-of-the-Month: Tansy Ragwort

The July WeedWise Weed-of-the-Month is tansy ragwort (Senecio jacobaea). Tansy ragwort is a class B noxious weed in the state of Oregon and is the invasive weeds species that we receive the most calls and emails about each year. This invasive weed was once actively enforced by the Clackamas County Noxious Weed Control Board, prior to its dissolution in 1989. As a result, many of the calls we receive from folks are not related to their own land, but concerns about neighboring property. These concerns are not unfounded!

Tansy ragwort is toxic to livestock and is known to cause mortality with ingestion of as little as 3% of total body weight. It is also known to contaminate hay and honey causing significant economic hardship to local agricultural producers.

Fortunately, tansy ragwort can be easily managed. The first step in this process is to develop a management plan for your property and then work systematically to implement it. The WeedWise program has developed a Tansy Ragwort Best Management Practices document to help landowners to be more effective in their efforts.

So help a hoof by controlling your tansy ragwort today! To learn more about the effects of tansy ragwort and steps you can take to manage this invasive plant, check out our July Weed-of-the-Month. If you are already managing tansy on your property contact us with any questions you may have.

Savoy Hawkweed Survey and Control!

This past month the WeedWise program participated in an effort to survey and control a new exotic weed in the upper portions the Clackamas River watershed. This newly identified species known as savoy hawkweed (Hieracium sabaudum) has not been previously known to occur elsewhere in Oregon. As a result, the WeedWise program is working closely with staff from the Mt Hood National Forest and the Oregon Department of Agriculture’s Noxious Weed Control Program to document the infestation.

Management of this species is complicated due to its close resemblance to a rare native hawkweed. As a result, much effort has been spent working with hawkweed experts from the herbarium at the Burke Museum to ensure that our identification is accurate. The WeedWise staff has also been working with botanists to identify key characteristics to allow for more reliable identification in the field.

As a new invasive species to Oregon, savoy hawkweed is still being assessed for a potential noxious weed listing in Oregon. Unfortunately, as a state-listed weed in Washington state, we already know the potentially damaging impacts this plant can have on natural systems if left unchecked. So the WeedWise program is taking action to contain this infestation and continue to survey and document locations for ongoing management. Check out some of the photos from our recent activities below.

Photos from the Field

What We Protect!

When working with invasive weeds, it is easy to fall into the mindset of “killing weeds”. All too often our focus is on what we are working against rather than what we are working to protect. So we wanted to take the opportunity to share just some of the photos of our wonderful natural areas and open spaces. We are fortunate to be working to protect some beautiful places across Clackamas County!

Photos from the Field


It’s Sandy-Salmon River Smackdown Time!

This month the WeedWise program has been coordinating with our partners from the Sandy River Watershed Council to kick off our 5th year of the Weed Smackdown along the Salmon and Sandy Rivers! This ongoing effort has focused primarily on the treatment of Policeman’s Helmet (Impatiens glandulifera), but also includes the survey and treatment of other priority invasive weeds here in Clackamas County.

This year has been a challenge! Sustaining momentum has been complicated due to the disbandment of our partners from Project YESS, as well as the recent departure of our previous WeedWise program Weed Smackdown lead. This disruption was also coupled with an unexpected gap in funding to support this project. Despite these complications, we are back on track and pressing forward for another great year. We are even planning on expanding our efforts into additional areas of the watershed!

Many thanks to all of our participating landowners living along the targeted reaches of the Sandy and Salmon Rivers. This project would not be possible with your cooperation and support! For those of you who may have received one of our outreach packets please consider signing our Permissions to Access and Treat form. This will document your willingness to participate in our program and allows us to treat these priority weeds at no charge to you. Enjoy the photos below and if you have questions about the Weed Smackdown please feel free to contact us today.

Photos from the Field

Rare Plant Surveys: Pale Blue-eyed Grass

One of the concerns the WeedWise program considers in dealing with invasive weeds is the recognition of their impact on rare plant communities in our area. The WeedWise program has recently been working with staff from the Mt Hood National Forest on developing a response to protect one rare species known as pale blue-eyed grass (Sisyrinchium sarmentosum). This interesting plant is not actually a grass but is a rare member of the iris family.

Pale blue-eyed grass is “threatened with extinction” and is considered to be “critically imperiled” in Oregon. It is currently a “candidate” for listing under the Oregon Endangered Species Act and is a “species of concern” at the national level.

To protect our local populations of this rare native and to avoid its potential listing, the WeedWise program has been surveying pale blue-eyed grass sites. This is no simple task! The plants are extremely small and grass-like making them difficult to find when growing amongst other vegetation. WeedWise staff took care to identify and flag individuals to both document their abundance as well as to then develop a better understanding of how these plant populations persist and spread throughout the site. The purpose of this effort is to develop site-specific actions that will enhance conditions for the pale blue-eyed grass without harming existing plants.

Our preliminary site assessments revealed significant threats from the encroachment of woody trees and shrubs into the grassland areas where they persist. These assessments also revealed threats from several invasive plants. Planning continues and it is anticipated that we will be able to take action on these populations in the coming season to address both the encroachment of woody vegetation and the threat from invasive weeds.

Photos from the Field

Clackamas River Invasive Species Partnership

This month the Clackamas River Invasive Species Partnership (CRISP) member organizations came together for our summer partnership meeting. This is one of two meetings that the WeedWise program hosts each year. This event allows members to share information about their efforts and learn how they are collectively contributing to an amazing amount of work in the watershed. This meeting was no exception!

At the meeting, we learned about new efforts to manage invasive plants like policeman’s helmet, yellow flag iris, purple loosestrife, and drooping sedge at CRISP partner managed properties. One partner alone reported planting more than 80,000 plants as part of their ongoing restoration efforts! We also learned about substantial new efforts planned to restore 70 acres of publicly-owned natural areas. We are so grateful for all of our CRISP partners and the energy they bring!

The WeedWise program activities for the current year were also well-represented. WeedWise Specialist Lindsey Karr was able to share about our CRISP-related efforts across the watershed. Lindsey reported that we mailed 696 landowners so far this year, with even more outreach planned for later this season. In the first half of 2018, the WeedWise program also surveyed 87 properties and carried out 150 invasive weed control treatments. These treatments targeted a diverse set of invasive weeds including garlic mustard, spurge laurel, policeman’s helmet, false brome, orange hawkweed, sulfur cinquefoil, goats rue, oblong spurge, milk thistle, meadow hawkweed, giant hogweed, Japanese butterbur, and shiny geranium.

In addition, the CRISP partners were also able to discuss eight new projects scheduled for this fall. The partners agreed to move forward on these projects. In support of these efforts, we will also be continuing to contact affected landowners. If you have received one of our mailings, please return the enclosed Permission to Access and Treat form to ensure that your property is surveyed and treated at no cost to you! If you have any questions about the program, please contact us!


Cooperative Weed Management Areas

The WeedWise program is very active with our local Cooperative Weed Management Areas (CWMA). We have two CWMAs within Clackamas County, the 4-County CWMA that serves that Portland-Vancouver Metro region and the Columbia Gorge CWMA that serves the Columbia River Gorge and surrounding areas. The WeedWise program currently administers both of these CWMAs.

With the recent departure of CWMA Coordinator Sarah Hamilton, the WeedWise program has been working with the CWMAs to refill the coordinator position. In the meantime, WeedWise program manager, Sam Leininger has been helping to facilitate communications between CWMA partners. Below are just some of the highlights of activities currently underway.


4-County CWMA

The 4-County CWMA has been busy preparing for the upcoming general meeting in Washington County. This event is being hosted by our partners from the Tualatin Soil and Water Conservation District and will highlight a lot of new activities underway throughout the region. The general meeting will be held at the Tualatin SWCD office (7175 NE Evergreen Parkway Suite #400, Hillsboro, OR 97124) on Wednesday, August 8th from 10 am to 12 pm. All are welcome!

The event will feature a number of interesting presentations including:

  • A Tualatin SWCD & CWS Invasive Species Program Update – Tyler Pedersen, Tualatin SWCD, and Rob Emanuel, Clean Water Services
  • A review of Invasive Rubus species in the Portland-area Community Science Project – Mandy Tu, Curator at the Hoyt Arboretum
  • Weed-Free Gravel Recertification Program – Beth Myers-Shenai, Oregon Department of Agriculture
  • ODA Biological Control Program – Joel Price, Oregon Department of Agriculture
  • Forum topic discussions led by CWS, THPRD, TSWCD, Metro, and USFWS
  • A discussion about hot-button weeds & Integrated Veg Management and treatment efficacy
  • CWMA Committees and Working Group Updates

The event will be followed by a planning meeting for this year’s annual 4-County CWMA Pull Together conference. So if you want to help and shape this year’s event. Now is your chance!

Don’t miss out on this great event. We will see you there!

Columbia Gorge CWMA

The Columbia Gorge CWMA has recently wrapped up its recent Stop The Invasion: Weed management 101 project. This project included the development of ten new Best Management Practices (BMP) to target commonly occurring weeds in the Columbia Gorge and surrounding areas. We are pleased to announce these new BMPS are now available on the Columbia Gorge CWMA website. Many thanks to our partners at Skamania County Noxious Weed Control, Washington State University Extension, the Washington Invasive Species Council and all of our Columbia Gorge CWMA partners for helping to make this effort possible. Thank you!

This past month, the Columbia Gorge CWMA also hosted its 2018 Field Day at Trout Lake. This annual event was a real treat to attendees. Participants learned about vegetation management efforts to support the recovery of Oregon spotted frogs, sandhill cranes, and several rare plant species. This event provided a great opportunity to connect with other land managers in the region. To see just some of the photos from this year’s field day check out the WeedWise Program’s photo album from the event.

More WeedWise Online and on Social Media

Did you know that the WeedWise program also hosts a website online that specializes in invasive weed related issues? Be sure to check out the website and read some of our recent articles over the last month. The WeedWise program is also active on social media, so be sure to follow us online!

Facaebook Twitter

 We hope you’ve enjoyed the July edition of the Prickly Thistle!

Thanks for your interest in the Clackamas SWCD WeedWise program

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Clackamas SWCD