Archive | Weeds

Detecting, controlling, and eradicating invasive plants are topics captured in the Weeds category. Invaders affect wildlife and crop production. In some cases they pose health risks to people and animals.

October Weed of the Month: Blackberry

Invasive blackberry photo by Sam Leininger

Invasive blackberry photo by Sam Leininger

You wrangled with the prickly vines in the spring and enjoyed those juicy sweet berries all through the summer, but now it’s fall and it’s time to take control of the blackberries! So, put on your heavy-duty work gloves and get to work on those vines! That’s right — autumn is the very best time to control this wide-spread and aggressive invasive.

Protect Creatures and People!

One reason to control blackberries in the fall to avoid disturbing nesting birds. In the spring, some birds will use the thorny brush to build nests and hatch their eggs. If you choose to use a chemical control, you will also want to avoid taking action when the plants are in bloom. Many of our important pollinators such as bees and butterflies may be at risk during flowering. When berries are on the canes, it is not only birds, but also people and other animals that are at risk from chemical applications. Fall is the safest time to control chemicals. Remember, ALWAYS FOLLOW THE LABEL and put safety first, for you and any unintended targets.

Pull On Gloves!

For manual control, it is important to arm yourself against the sharp thorns by wearing thick gloves, sturdy long pants, and long-sleeved shirts or jacket. Those who are unprepared will suffer the consequences with nasty scratches. Use board or plywood to mash down blackberry canes, and to access densely infested areas. If your ground is level or has little slope you may also be able to mow down the canes (sometimes a brush cutter is necessary). This will remove the bulk of the plant. If you wish to use the mowing method for permanent control, you will need to continue this process at least 4 times per year, for several years, to exhaust the energy in the root system. Remember to check for any nesting birds in the spring, but if you keep on top of the mowing there will not be a good place for the birds to build a nest. If using goats to remove the blackberries, you may still want to get rid of the old canes first and then let the goats periodically graze the new growth for long-term control.

Can You Dig it?

If you choose to remove the entire plant, including the roots, you will have much easier access with the top growth removed. Digging or tilling can take out the root system, but be sure to remove as much root material as possible. Even small pieces can re-sprout, so try raking up all remaining bits. If you are working on a slope, make sure you have enough time in the fall to reseed any disturbed areas to avoid erosion caused by fall and winter rain. If not, root removal might need to wait until spring.

Weed Alert!

Warning: expect a flush of weeds in the old blackberry patch. A build-up of weed seed may remain dormant under the brambles for years and once exposed to sunlight they will sprout. Weed control is just another step in the process.

Removal of invasive blackberry requires persistence and patience, but success comes to those who persevere! For more detailed information on blackberry control, check out our Best Management Practices on the WeedWise Website.

District Seeks WeedWise Specialist for Term Project

WeedWiselogoClackamas Soil and Water Conservation District seeks qualified candidates for a WeedWise Program specialist position. All applications materials must be submitted to the District no later than 4:30 PM on Oct 14, 2016.

About the position

The WeedWise Program Specialist is a full-time, at-will non-exempt position that will provide project management to the Clackamas Soil and Water Conservation District’s WeedWise Program and will assist with field-based weed control work, outreach efforts, data collection, and administrative tasks.

The WeedWise Program Specialist will assist with the District’s priority weed control initiative and in support of the Clackamas River Invasive Species Partnership (CRISP) ( This priority weed control initiative involves: surveying and documenting priority invasive species; project planning and management; outreach to landowners; overseeing contracted weed control activities; and treating noxious weeds using a variety of integrated pest management (IPM) practices. The WeedWise Program Specialist will also assist the WeedWise Program staff with planning and implementation of additional program activities and initiatives as required.

Minimum Qualifications

The minimum qualifications for the WeedWise Program Specialist are:

  • A Bachelor’s degree in biology, ecology, environmental science, weed science, natural resource management, or a related science, or three years of comparable experience working for a natural resource related organization, agency, or business;
  • Experience working with on-the-ground implementation of conservation practices associated with invasive species/native plant management;
  • Experience collecting field data and maintaining field notes;
  • Good oral and written communication skills;
  • A demonstrated proficiency using personal computers and mobile field based technology;
  • Strong project management skills;
  • Must have a Public Pesticide Applicator’s License, or be willing to secure a license within three months of hire date;
  • A demonstrated proficiency using Microsoft Office and ESRI ArcGIS;
  • The ability to work independently and as part of a team.
  • A valid driver’s license and a good driving record.

Wages and Benefits

The District offers a competitive wage and benefits package. The starting wage will be up to $21.00 per hour for this full time position.

How to Apply

Applicants must provide a cover letter, resume, and a completed District application form. All application materials are available through the links below or at the Clackamas Soil and Water Conservation District office. We will accept electronic or regular mailed submissions only. No Faxes will be accepted.

Application Materials

Submit your application materials to:

Clackamas Soil and Water Conservation District
ATTN: Sam Leininger, WeedWise Program Manager
221 Molalla Ave, Suite 102
Oregon City, OR 97045


The Clackamas Soil and Water Conservation District prohibits discrimination against its customers, employees, and applicants for employment on the basis of race, color, national origin, age, disability, sex, gender identity, religion, reprisal, and where applicable, political beliefs, marital status, familial or parental status, sexual orientation, or all or part of an individual’s income is derived from any public assistance program, or protected genetic information in employment or in any program or activity conducted or funded by the District. The District is an Equal Opportunity Employer.

Clackamas River Invasive Species Partnership Project Moves Forward

The Clackamas River Invasive Species Partnership (CRISP) was recently awarded funds totaling $431,250 from Portland General Electric (PGE) through the Clackamas River Hydroelectric Project Mitigation and Enhancement Fund. This award adds to the other contributions from CRISP partners totaling $1,168,750 to implement a comprehensive plan for coordinating the management of invasive weeds in the Clackamas River Basin.

Invasive Weeds Affect Us All

WeedWiselogoInvasive weeds cost Oregon residents millions of dollars each year by reducing the productivity of farmland and decreasing property values, as well as impairing water quality and degrading natural areas important for fish and wildlife. The partnership goals are to mitigate these impacts by helping agencies, organizations, and private landowners work more effectively together to improve these conditions.

“Initial efforts in implementing the goals of the CRISP project will focus on targeted areas of the watershed where partners can begin working together across property lines to improve invasive species management ,” states Sam Leininger, manager of the Clackamas Soil and Water Conservation District’s WeedWise program. “The CRISP partners have identified areas in four priority subbasins where we can hit the ground running and immediately improve conditions in the watershed.”

What Landowners Should Expect

The first step in this project will include landowner outreach to request access along the Clackamas River and its tributaries to conduct site surveys for priority invasive weeds. The survey work will then allow the CRISP partners to coordinate invasive species treatment and restoration efforts where necessary. The treatment and restoration on a property may take several years.

“There are a long list of partners that are contributing their time and effort to this project,” says Leininger. “The CRISP participating partners include the Clackamas Soil and Water Conservation District, the Clackamas River Basin Council, Metro, the 4-County Cooperative Weed Management Area, Bureau of Land Management, Clackamas County Parks, Clackamas County Water Environment Services, Natural Resource Conservation Service, North Clackamas Parks and Recreation District, Oregon Department of Agriculture Noxious Weed Control Program, Oregon Parks and Recreation Department, Portland General Electric, and the United States Forest Service. The CRISP project will help to build upon existing efforts within the Clackamas watershed and ensure that we can all do our work in a better way.”

To find out more about the CRISP project, please visit our Weedwise page.

Tansy Ragwort Poisons Livestock and Neighborly Relationships!

Tansy ragwort has long tormented hay producers and rural landowners who graze livestock. Horses and cows are especially susceptible to this poisonous weed.

In open fields, grazing animals will generally avoid eating tansy ragwort, but in heavily infested pastures they may have few other options. Contaminated hay is particularly a problem because it becomes impossible for feeding animals to avoid consumption.

Tansy Ragwort is manageable

Tansy Ragwort is manageable

Tansy ragwort has a long history in Clackamas County. It was one of the few plants regulated under the former county noxious weed control district that was formed in 1949. At that time, landowners in Clackamas County could be cited for having flowering plants on their property. Back then, neighbors would come together for community tansy pulls to keep their horses and livestock safe and to avoid the dreaded visit from the weed inspector.

In the 1960s, several insects were introduced as biological controls to reduce the abundance of tansy ragwort. These insects feed on the plants and weaken or kill the tansy. The most recognizable of these is the crimson red Cinnabar moth. The caterpillar for the moth feeds on the flowering plant during the summer months.

With the introduction of a flea beetle in 1971, we had the one-two punch needed to reduce the tansy ragwort problem to relatively low levels. Following the reduction of tansy ragwort, Clackamas County dissolved the Clackamas Noxious Weed Control Board on August 3rd, 1989 citing the effectiveness of the biological controls as well as budget constraints as the chief reasons for its dissolution.

In the years since the weed board was dissolved, tansy ragwort has continued to persist in Clackamas County, but typically at much lower levels than those encountered in previous generations. The biological controls introduced in the 1960s and 1970s are still working on our behalf!

In years with especially mild and wet springs we see a strong revival of tansy ragwort seedlings. In these years, the effects of the flea beetle are dramatically reduced and we see tansy ragwort soaring to the top of Clackamas County’s least wanted list of weeds.

Cinnabar Moth caterpillar on Tansy Ragwort

Cinnabar Moth caterpillar on Tansy Ragwort

This year, folks throughout Clackamas County are once again seeing the yellow flowers blooming in their fields. They are calling in to the Clackamas Soil and Water Conservation District (SWCD) asking for assistance in controlling this weed. But by the time tansy flowers appear, the best management of this weed is a good pair of leather gloves, a strong back, and a healthy dose of perspiration from pulling mature plants. Mowing and cutting plants only spreads the poisonous vegetation around, making it more difficult for livestock to avoid. Tansy ragwort is normally a biennial plant, but mowing can cause it to behave like a perennial, meaning it will tend to come back year after year.

Some of our customers remember the neighborhood tansy ragwort pulls that were common many years ago…but now they seem to be a thing of the past. Tansy still poisons livestock but also affects the relationships of once cordial neighbors. Each year the Clackamas SWCD receives a large number of calls from neighbors complaining about their neighbors tansy plants.

There are no longer weed inspectors in Clackamas County, so our best recommendation is to work with your neighbors to control tansy ragwort. We have developed a Tansy Ragwort Best Management Practices document to help folks develop a management plan for their property.

Despite the onslaught of tansy ragwort, remember that all is not lost! Tansy ragwort is manageable. If you have a lot of tansy plants and are feeling overwhelmed, focus first on areas where grazing animals are present or along fence lines to help with your neighborly relations. Pull flowering plants and dispose of them as trash or pile them up away from grazing animals and then burn them when allowable.

If plants are already going to seed, cut off the seed heads and dispose of as trash. Try to avoid spreading seed further. Follow up the next spring by pulling emergent rosettes when the ground is still wet or use an approved herbicide recommended by the Pacific Northwest Weed Management Handbook that is appropriate for your property. Be sure to always read and follow the label directions on any herbicides you purchase. Work to keep good vegetated cover on your ground. Avoid overgrazing, reseed good pasture grasses as needed, and implement rotational grazing practices when possible to rest vegetation over time.

Don’t let Tansy Ragwort poison your livestock, or your relationship with your neighbors: do the neighborly thing and control your tansy ragwort. Happy Pulling!


Call for Citizen Scientists!

Pacific Northwest Invasive Plant CouncilThe Pacific Northwest Invasive Plant Council, a non-profit conservation organization, is hosting two FREE workshops to train citizens to identify important invasive plants. Join a regional volunteer effort to detect and eradicate invasive plant species!

In just 2.5 hours of your time, you will learn how to identify priority invasive plants and how to record basic data. Participants also learn methods of manual invasive weed removal. Equipped with this new knowledge, volunteers with be able to conduct invasive plant surveys that are of great value to local land managers. Your efforts will directly support the maintenance of healthy ecosystems.

If you work on or spend time enjoying public lands, or would just like to learn more about invasive plants, we invite you to attend one of the upcoming trainings.

April 27, 2016, Wednesday at 1:00 pm-3:30 pm Sandy, OR
Sandy Community Center
38348 Pioneer Blvd, Sandy, OR 97055;
Parking is available along the side and at the back of the building.
Hosted by: David Lebo, Westside Zone Botanist, Mt. Hood National Forest and Sam Leininger, Clackamas Soil and Water Conservation District and the Columbia Gorge CWMA

April 28, 2016, Thursday at 9:30 am-12:00 pm Vancouver, WA
Fort Vancouver, Pearson Air Museum
1115 E 5th Street, Vancouver, WA 98661.
Hosted by: Carol Chandler, Wildlife Biologist, Gifford Pinchot National Forest and Emily Stevenson, Skamania Noxious Weed Board, Columbia Gorge CWMA

Seating is limited; if you would like to attend one of these free trainings, please RSVP to Julie Combs to reserve your place or call 615-812-5295.

Participants may receive WDSA or ODA pesticide license re-certification credits (2 credits) pending approval.

Citizen science volunteers will receive an invasive plant identification booklet along with survey forms and instruction on how to report findings. Volunteers are asked to conduct 1-2 surveys over the 2016 field season.

The Pacific Northwest Invasive Plant Council works in partnership with the USDA Forest Service, Washington Dept. of Agriculture (WSDA), Department of Natural Resources, and other state and local groups on a Citizen Science Early Detection Rapid Response program. Funding from the National Forest Foundation, National Fish and Wildlife Foundation, the WSDA, and others has allowed the group to gear up for their fifth year to search for priority and newly emerging invasive plants in our National Forests, National Parks, and other public lands.

The Pacific Northwest Invasive Plant Council is excited to recruit new volunteers and inspire their current volunteer base to search for and report new invasive plant populations. There is a great need to document emerging invasive plant populations on all public lands.