The Prickly Thistle: A June 2018 WeedWise update

Welcome to the June 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!

Summer is here!

The month of June brings with it the official first day of summer. Like the changing seasons, June is also a month of transition here at the WeedWise program.

The “spring sprint” to control priority invasive weeds like garlic mustard is largely over, finally freeing up time in our schedule to treat many of our other priority weeds. Invasive weeds like orange hawkweed, giant hogweed, policeman’s helmet, false brome, oblong spurge, and sulfur cinquefoil are all on our target list.

The summer season also brings the first flush of blooms from tansy ragwort. Based on the number of calls to the WeedWise program, tansy ragwort is hands down the most hated weed in Clackamas County. As the yellow flowers start to bloom the calls start rolling in from concerned horse and livestock owners. Tansy ragwort is toxic to livestock, causing permanent liver damage and ultimately death if animals consume too much. Fortunately, most animals avoid the plant if given sufficient desirable forage. But June is also the month when hay is being cut and baled. Tansy is especially a concern when it is baled with hay. Once baled, animals are unable to avoid the tansy ragwort and poisonings are more likely.

So help to “spread the word and not the weeds” and talk with your neighbors. If your a hay producer may sure to remove toxic tansy from your fields. Better yet, go a step further and certify your field as weed-free to maximize the value of your hay crop! If you are livestock owner, reject any hay that contains tansy or other toxic plants to ensure the health of your animals. The livestock of Clackamas County will thank you!

If you are battling weeds on your property, please feel free to contact us with your questions. We are here to help!

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

Samuel Leininger

WeedWise Program Manager


Celebrate National Pollinator Week!

June 18- 24th was National Pollinator Week and the perfect opportunity to talk about pollinator health. Much of our work here the WeedWise program is directed to help protect native plants that our pollinators rely upon for food, shelter, and rearing habitat for their young. Invasive weeds can adversely impact the diversity of native plants in our area and ultimately reduce the number of associated pollinators as well.

Unfortunately, we often see situations, where a diverse plant community is replaced by a monoculture of invasive weeds. Although weeds can be important nectar sources for some pollinators at certain times of the year, they ultimately support fewer pollinators. Invasive plants reduce the diversity of host plants, that can lead to “food deserts” for pollinators after the weeds have finished blooming. By contrast, more diverse plant communities have wave after wave of blooms throughout the year to support pollinators. From the perspective of our native pollinators, areas infested by invasive weeds are akin to having a supermarket that only carries food for one month out of the year.

So help protect out local pollinators by controlling your invasive weeds. Check out our recent pollinator week article, that includes the Top 10 WeedWise Tips for Protecting Pollinators.

You can also learn more about pollinators on the Pollinator Week online.



June Weed-of-the-Month: Policeman’s Helmet

The WeedWise weed-of-the-month for June is policeman’s helmet (Impatiens glandulifera). Policeman’s helmet is a class B noxious weed in the state of Oregon and is one of our high priority weeds for control and eradication in Clackamas County. Policeman’s helmet is one of the fastest growing annual plants and can reach a height up to 10 feet in a single growing season!

Seeds from policeman’s helmet can spread great distances, first through its explosive seed pods that are known to launch seeds up to 20 feet away. The seeds are also secondarily spread by water along streams and rivers where it typically invades. People are also one of the primary ways that these plants spread. Also known as “poor man’s orchid”, the showy flowers of policeman’s helmet have led to some unsuspecting gardeners to collect and trade seed. Not only is the distribution of this plant prohibited, but this state-listed noxious weed is not something you would want to unleash on your property.

Policeman’s helmet can have a significant impact on streamside plant communities. Its rapid growth allows it to quickly colonize a site, thereby displacing native vegetation. Unfortunately as an annual plant, in the winter and early spring months, policeman’s helmet plants are gone leaving soil bare and exposed. During rain and spring high water events, these exposed soils can erode which degrades water quality and habitat for fish and people.

The WeedWise program has been working for a number of years along the Salmon River within the Sandy River watershed to control policeman’s helmet. This effort is undertaken in cooperation with the Sandy River Watershed Council and the ongoing support of hundreds of local landowners. This effort has become affectionately known as the Weed Smackdown and is a major initiative for the WeedWise program.

To learn more about policeman’s helmet check out our June Weed of the Month Post and on the ODA Noxious Weed Program’s Policeman’s Helmet Weed Profile.

Lolo Pass Hawkweed Control!

This past month the WeedWise program was proud to participate in an effort to control invasive orange hawkweed and meadow hawkweed in the upper portions the Sandy River watershed in Clackamas County. This work is an ongoing effort between the WeedWise program and our partners from the Mt Hood National Forest, the Oregon Department of Agriculture’s Noxious Weed Control Program, and Portland Water Bureau.

The invasive hawkweeds have a significant impact on grassland sites and natural areas. Orange hawkweed, in particular, is a class A priority noxious weed and is the highest priority for control and eradication. The area where we have been working is one of the largest and most heavily impacted areas in the state. The WeedWise program has been working collaboratively to keep this infestation contained and prevent it from spreading into other areas.

The area impacted by the invasive hawkweeds is a powerline corridor surrounded by forest and several recreational sites including the Pacific Crest Trail. the site also borders the nearly pristine Bull Run Watershed that serves as the municipal watershed for the City of Portland. The site is host to a variety of wildflowers, so we are working hard to help keep these diverse resources protected. Check out some of the photos from this activity below. For even more photos be sure to check out the WeedWise webpage.

Photos from the Field


Out at the Beavercreek Farm

WeedWise staff and contractors were recently at our Beavercreek Farm performing some spring maintenance. This effort is undertaken in conjunction with the annual haying of our fields. WeedWise Specialist, Jeff Lesh was on hand to survey our property for sensitive plants and to do an inventory of plants on the farm. A nesting bird survey was also undertaken to ensure that nesting birds would not be directly impacted from our weed control efforts.

Activities at the farm were focused on sweeping through the fields to remove any remnant tansy ragwort plants before the fields were hayed. In addition to our spring weed control efforts, we also cut firebreaks along our fencelines and around our buildings to help protect the farm from a fire. Crews also carried out some opportunistic treatments of blackberry, ivy, shining geranium, and holly.

We are very grateful for the hard work of our WeedWise staff and contractors for helping to maintain the Beavercreek Farm. To learn more about the Beavercreek Farm check out the Beavercreek Farm website online.

Photos from the Field


Priority Invasive Weed Staff Training

Identifying invasive plants can be a real challenge. This is especially true when dealing with rare or uncommon weeds like those targeted through our rapid response initiative. In many instances we hope that some of our invasive weeds are never encountered by folks, so it can take some real effort to familiarize ourselves with a plant that may rarely be seen.

To combat this effort, the WeedWise program recently hosted a training for the Clackamas SWCD’s technical staff. The training provided an opportunity for our staff to test their knowledge and familiarize themselves with difficult and confusing species. We spent a lot of time working through problematic groups of plants like the hawkweeds, knapweeds, and spurges to make sure that our staff can better identify these priority invasive weeds.

Many thanks to all of our staff for participating!

Photos and video from the event:


Rare Plant Surveys: White Rock Larkspur

In working to protect Clackamas County from the impact of invasive weeds, we often consider the susceptibility of a site to invasion by weeds. Whether we are working in an agricultural field, a neighborhood, or a natural area, we frequently assess the potential harm to a site should it be invaded. Few sites are as sensitive to the threat of invasive weeds as those with rare, threatened, or endangered species.

This month WeedWise Specialist, Jeff Lesh, was out surveying a few populations of the endangered flower white rock larkspur (Delphinium leucophaeum). This rare plant is under threat from invasive species and is a target for conservation as identified in the Oregon Conservation Strategy.

In our area, white rock larkspur is limited to rocky outcroppings and remnant grasslands. At these sites, the larkspurs are under constant pressure from non-native grasses and broad-leaf weeds. One weed of concern is the garlic mustard that we have observed actively invading larkspur populations. WeedWise staff visited a number of sites to assess known larkspur populations near our active treatment areas. This was carried out to ensure that our current activities not only avoid any impact to the larkspur but also so we can inform our efforts to buffer these rare wildflowers from future invasion.

Photos from the Field


The Backyard Habitat Certification Program expansion is complete!

This month the Backyard Habitat Certification Program wraps up its first spring operating across the entire service area of Clackamas County. This ongoing effort sponsored by the Conservation District is helping to promote the management of invasive weeds in urban yards and landscapes as well as promote the use of native plants to promote wildlife and water quality.

In this year’s final tally, the Backyard Habitat Certification Program reports 181 new properties enrolled and assessed this year. Of the properties assessed, twenty of them became certified backyard habitats! These certifications, in the first year of expansion, demonstrate the existing commitment of local landowners to support wildlife and to promote backyard habitat. Many thanks to all of our BHCP participants! For more information about the amazing level of participation of this program in our area check out the Backyard Habitat Program Participation Map.

The Backyard Habitat Certification program is administered by Columbia Land Trust and Audubon Society of Portland and is a great new resource for Clackamas County residents. The program helps landowners target their invasive weeds, and develop their yards into urban sanctuaries for wildlife. So join in the fun and sign up today!


Clackamas River Invasive Species Partnership

The WeedWise program has been very busy controlling priority invasive weeds in association with the Clackamas River Invasive Species Partnership (CRISP). Invasive weeds like orange hawkweed, giant hogweed, policeman’s helmet, false brome, oblong spurge, and sulfur cinquefoil are all on our targeted list.

One weed of particular interest this month is Giant Hogweed (Heracleum mantegazzianum). This class A noxious weed is a high priority in Clackamas County because of its potential to cause severe burns or blindness after exposure. The sap of hogweed leads to severe light sensitivity. Exposure to light following contact with giant hogweed can cause severe burns that can last for years.

A recent news report found that this plant is still on the move. Fortunately, we have only a handful of sites here in Clackamas County and we are working really hard to keep it that way!

Giant hogweed is very closely related to our native cow parsnip. Although similar, giant hogweed is much larger with deeply cut leaves, bumpy splotches on its stem, and coarse bristly hairs. If you think you have giant hogweed on your property, snap some photos and report them to the Oregon Invasive Species Hotline. As a priority weed, we can help control this dangerous plant for affected landowners. We are currently working on a number of sites in Clackamas County in cooperation with the Oregon Department of Agriculture’s Noxious Weed Control Program.

As part of our CRISP lead treatment efforts, WeedWise Specialist, Lindsey Karr has been out treating this priority noxious weed and many others throughout the Clackamas Basin. We are 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 feel free to contact us!

Photos from the Field:


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 Sarah Hamilton, as CWMA Coordinator, 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.


Happy Retirement to Vern Holm, Western Invasives Network Coordinator

All of us here at the WeedWise program gratefully acknowledge the years of service and the many contributions of Vern Holm, Coordinator of the Western Invasive Network. The Western Invasives Network (WIN) is a local partnership organized to help develop and administer Cooperative Weed Management Areas across western Oregon and southwestern Washington.

Vern has long been a driving force to improve invasive species management in our area. In helping to foster the development of the 4-County CWMA and Columbia Gorge CWMA, Vern has greatly improved the management of invasive weeds in our region. Whenever folks were looking for an answer to their weed problem, Vern either knew the answer or knew who to ask. His role serving as a conduit for information sharing between active partners has served to strengthen programs across the region.

After his years of service, Vern is preparing to enjoy a well-earned retirement. We couldn’t be happier for him, but know that we will miss having him around as a resource and friend.

We thank for Vern and wish him all the best in his many new and wonderful adventures, and maybe a well-deserved nap or two!

Happy Trails Vern!


4-County CWMA

The 4-County CWMA recently held its 2018 Field Day. This annual event was hosted by our friends from Clark County Vegetation Management and featured many interesting topics. Attendees learned about invasive weed management practices from Columbia Land Trust to promote sandhill cranes. These innovative practices even included promoting one noxious weed, yellow nutsedge as a food source for the cranes.

We also thank the kind folks at Plas Newydd Farm, for sharing their conservation work in support of their new wetland mitigation site.

If that wasn’t enough, we also had a chance to see several new weeds including slender-flower thistle and Cypress spurge.

This annual event is a great opportunity to connect with other weed control and restoration experts through the region. Many thanks to everyone that participated. Check out the many photos from the event on the 4-County CWMA Field Day 2018 Album on the WeedWise Facebook page.

Columbia Gorge CWMA

The Columbia Gorge CWMA has been wrapping up their 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. Many thanks to 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!

The Columbia Gorge CWMA is also busy planning the 2018 Field Day at Trout Lake. This field day will focus on vegetation management to support the recovery of Oregon spotted frogs, sandhill cranes, and several rare plant species. This should be a great event and great opportunity to connect with other land managers in the region!

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 June edition of the Prickly Thistle!

Thanks for your interest in the Clackamas SWCD WeedWise program

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Clackamas SWCD