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To offer a suggestion or report an error on the King County Noxious Weeds Web site, please contact Sasha Shaw, education specialist.
King County, Washington Noxious Weed Identification and Control

KC Weed News - March 2008

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Topics BelowScotch broom buds and flower in March - click for larger image

Weed of the Month: Scotch Broom (Cytisus scoparius) , Class B Non-Designate Noxious Weed in King County, Washington

There are three statements I hear most often about Scotch broom (or Scot’s broom, which is perhaps the correct common name but just not as commonly used). First, people tell me that they hate this plant because they are allergic to it. Second, people tell me that Washington State Department of Transportation plants it along the highways. And third, I hear from newcomers to the area that they are sure it is a native plant because of how widespread it is. Allow me to respond to each of these half-truth, half-myths. First, the pollen of Scotch broom is very heavy and so not very likely to be blowing in the wind to irritate people with allergies. However, there does seem to be a strong correlation between Scotch broom flowering and people being miserable when they drive by thick patches of it. Perhaps there is a reaction due to the strong odor or other factors. In any case, it doesn’t seem conclusive one way or another, so if you have a reaction to this plant, by all means try to get rid of it if you can.

Secondly, although the state and other agencies did perhaps use Scotch broom in the past for roadside plantings (there is some discrepancy when I ask transportation officials this question), they are no longer planting Scotch broom along Washington highways. When you see a newly constructed off-ramp or cleared highway shoulder suddenly sprout a thick field of Scotch broom, this is the legacy of the many years of Scotch broom seeding in the area and not because of a misguided landscape plan. Unfortunately, broom seeds are so tough and so long-lived, that it is almost inevitable that this plant shows up whenever land is cleared, especially in highway rights-of-way where conditions are ideal for Scotch broom to prosper.

Finally, for those who believe this plant to be native, they are of course sadly mistaken. Invasive plants can become so entrenched and widespread that it is hard to tell them apart from native species (just look at Himalayan blackberry). However, historical records do show us that Scotch broom was introduced from Europe numerous times over a large number of years, beginning before 1900 and continuing to the present (people continue to plant varieties of this weedy species in spite of a state quarantine against selling it is Washington State).

As you may have noticed, Scotch broom can be found throughout most of Washington State except in the southeastern corner of the state. It is most widespread west of the Cascades and is also common all up and down the west coast from British Columbia to California. According to the records at the UW Herbarium, the first specimen in Washington was collected in 1892 in King County. The location is just listed as Seattle but the plant was described as naturalized, so it appears Scotch broom was already on the move before the 1900’s. In the 1920’s, collections were made from the campuses of WSU and UW as well as western Oregon and Thurston County. In the 1930’s, Scotch broom was found on Upper Tahoma Creek on Mount Rainier as well as numerous other places around the western part of the state. Botanical collections are just a snapshot of where plants occurred historically, but these examples show us just how widespread Scotch broom was by the early 1900’s and how far into wilderness areas it had already spread by the 1930’s. So it should come as no surprise that this is one of the most common weeds in our region now, ranging from urban to rural, disturbed to natural lands, coast to mountains.

If you are struggling with your own populations of this pervasive plant, then you can take heart that it has had a huge head start. If you add to this the longevity of the seeds (I am told they are viable 60 years or longer!), you definitely have to take the long view if you are going to successfully get rid of Scotch broom. Sometimes it might seem that nothing works to get rid of the stuff, but what is probably happening is new seedlings are popping up from the seeds in the soil or from seeds that are moved to the site on equipment or fill materials or even in soil or water moving naturally into the area. The one consolation with this plant is that individual plants don’t seem that tough to kill if they are pulled up with a weed wrench or treated according to the label with herbicide. Older plants can even be killed simply but cutting them down, if they are stressed sufficiently by summer drought. However, one thing I can assure you is that young green Scotch broom can live indefinitely if it is mowed. And it will most certainly out-live any mower you use to try to cut it.

In parts of the state where Scotch broom is still getting established, such as Kittitas and Chelan Counties, it is well worth the effort to try to control every population. In King County, we really need to focus on removing this plant from our parks and natural areas as well as the roadsides and rivers. However, this is a long term undertaking and will require a great deal of effort and patience. The only area were we are requiring control at this time is on I-90 east of North Bend (past Mile Post 34) and on Highway 2 where it comes into our county before heading over Stevens Pass. Fortunately, numerous city, county and state crews, community groups, volunteers, and private landowners are getting serious about removing Scotch broom. This is a great trend and perhaps we can hope for a time when this plant is much less dominant in our parks and natural areas in the county, and perhaps even in our own neighborhoods.

Other than the highways near the mountain passes, we are not tracking infestations of Scotch broom. However, if you or anyone you know would like information on removing Scotch broom, please contact our office at noxious.weeds@kingcounty.gov or 206-296-0290 or check out our materials on Scotch broom available online. Also, we have several weed wrenches available to loan out for free to King County citizens who would like to remove Scotch broom. Just give our office a call or drop us an email to reserve a weed wrench.

Weed Tips for March

Keep a lookout for gorse, flowering this month . Keep your eyes out for the fragrant yellow flower clusters on large, spiny bushes. Expect to find this plant along coastal areas and in forests on well-drained soils. We have had great success keeping gorse down to very low levels in King County. Help us keep it that way! Pulling or digging up this plant is possible while the soil is loose but you may need a weed wrench and heavy duty gloves.

Check pastures for toxic weeds. Animals will be more likely to graze poisonous plants if the grasses are still too short or sparse so check fields before setting animals out. Look for rosettes of tansy ragwort, milk thistle, and poison-hemlock and control them before letting the animals graze. For information on other poisonous pasture plants, contact your local extension office or conservation district. A handy summary of poisonous plants in western Washington can be found on our brochures page.

Watch out for giant hogweed in urban areas, parks, and anywhere else it has been spotted in the past. Check the noxious weed map for King County to see if it has been seen in your area. Hogweed’s large, jagged leaves and thick, purple-blotched stems should be tall enough to spot emerging above most other plants now and the plants will be easier to manage before they get full grown. Look for small seedlings and immature plants around the more obvious mature plants but be sure not to confuse non-native giant hogweed with similar native species cow parsnip and coltsfoot, also about the same size right now. Digging up hogweed this time of year isn’t too difficult, but be sure to use caution to avoid getting the sap on your skin because it can cause painful blisters and scarring. Contact our program if you find this plant in a new location in the county.

It’s garlic mustard time.Garlic mustard rosettes have been waiting all winter for their March growth spurt and will be flowering before you know it. If you had garlic mustard last year, go back to the same places and look for rosettes now to plan how to control them. Be sure to contact our program if you find any new populations of garlic mustard or if you would like help planning your control work for the year!

Fix trouble spots before the weeds take over. Disturbed areas in lawns, pastures, woods, and other places will fill in with seedlings of annual and biennial weeds like herb Robert and bull thistle. Spreading perennials like Canada thistle and spotted knapweed will move in quickly as well. Walk trails, fields and yards to spot trouble areas that will need re-seeding or mulch to keep back weeds.

Look for bindweed (morning glory) now while it is still small. Do you remember where bindweed was covering fences and plants last year? If you look around the same area, you will undoubtedly see small new stems coming up. Pulling these now will be much easier than after they wind themselves around your garden plants and everything else in their way. Also, if you can apply cardboard with wood chips on top over the area, that will weaken the bindweed and you will be able to pull it up much more easily later in the summer. Remember, this plant can sprout from stem fragments, so gather the stems and dispose in yard waste.

Sign up Now for King County Noxious Weed Workshops

We are taking registrations for our annual noxious weed workshops for vegetation management crews and others who need to identify and manage noxious weeds. This year we are pleased to have WSU researcher Tim Miller in addition to several of our own noxious weed specialists to teach a broad range of topics on noxious weeds. Topics include: state noxious weed list; identifying new and unusual noxious weeds; control of key weeds including garden loosestrife, purple loosestrife, phragmites, hawkweeds, knapweeds and thistles; noxious weed control on rights-of-way, disturbed areas and wastelands; weed identification with live specimens; WSU research results for control of a variety of noxious weeds; and a review of knotweed control on King County rivers. The full agenda is on our workshops page. Both classes are free and open to the public. WSDA pesticide license recertification credits have been requested for these classes (4 credits requested). Register at 206-263-6468 or sasha.shaw@kingcounty.gov. Please provide your name, agency or company, number of attendees and your contact information.

Progress Report for Noxious Weed Control in King County: 2007 Annual Report

As we begin our work for the 2008 season, it is an important time to reflect on our progress and performance in the previous season. We welcome our partners and the citizens of King County to join us in reviewing our progress to date in order to be sure we are on the right track and making the best use of the public investment in our program. The King County Noxious Weed Control Board 2007 Annual Report summarizes our work and analyzes the performance measures we use to track our progress toward our goals and mission. We welcome your review of this work and any input you have for how we can work effectively towards our mission to minimize the impacts of noxious weeds to the environment, recreation, public health and the economy. We are pleased with the effectiveness of our work program and feel optimistic about our ability to continue making progress towards this mission. The Annual Report and its appendices are available online. To request a printed copy of the annual report, contact our office at 206-296-0290 or noxious.weeds@kingcounty.gov.

Searchable Noxious Weed Map for King County Updated and Enhanced

Would you like to know where regulated noxious weeds have been found in King County? Or which watersheds or regions they are impacting? Have you ever wondered if there are Class A or B noxious weeds near your property? Or on a parcel you are considering for purchase? You could find out by calling our office. But if you’d rather find out from the comfort of your own computer, you can search our noxious weed database online by way of the county’s iMap tool. This site does require a highspeed connection but does not require any special software. Just go to our maps page and click on King County Noxious Weeds - Interactive Map . It can take awhile to load the whole map but if you zoom in to an area it can go more quickly. The map defaults to showing the most widespread of the regulated noxious weeds. If you want to look at all of the regulated noxious weeds, click on the “All Noxious Weeds” check box on the right column. New for 2007, we also have separate layers for the most recent year (2007), for all previous years grouped together, and for Class A and Class B weeds consolidated into one layer.

Getting around in the iMap viewer is fairly easy by using the tools on the left and the layers and features on the right side – zoom in on an area to see more detail, use the Property Search button to zoom in to a particular property, get weed information by using the information button (i), add or remove features and layers (rivers, roads, urban growth line, etc) and more. If you would like more information on using this tool, please contact us at 206-296-0290 or email Dennis Chambreau.

Job Openings at King County Noxious Weed Program

With every weed season, there are always changes. Sarah Baker, weed specialist for the Issaquah-Renton-Bellevue-North Bend-Snoqualmie area, has taken another position and won’t be returning to our program this year. We are sad to see such an important member of our team move on. We will be hiring her replacement this spring and the position information and application instructions are available on the King County jobs website. Applications will be accepted through March 17.

We are also planning to hire a short term temporary weed control field assistant for the peak of the weed season this year. The position will last approximately from June to September. The main goal of this new position is to assist with our knotweed and other special projects. We expect to be posting the job announcement in mid to late April. For information on either position, please contact Steve Burke at 206-205-6927 or steven-j.burke@kingcounty.gov.

County Transportation to Begin its Annual Roadside Weed Control Program in April

The County Road Services Division is one of our most important allies in the effort to stop the spread of noxious weeds in the county. In a recent news release, the Roads Division announced that they are beginning their annual weed program on April 1 and will cover roads in unincorporated areas of the county and in the cities of Burien, Covington, Maple Valley and Woodinville. Noxious weeds on the roadside will be one of their primary targets in addition to vegetation management for safety and road maintenance. In particular, they will be removing all tansy ragwort from rights-of-way as well as other state-regulated noxious weeds.

As in past years, residents who do not want crews to spray a county right-of-way that abuts their property may post “owner will maintain” signs. However, they need to first sign an agreement with the county to maintain the right-of-way themselves. Maintenance agreements must be completed and returned to the Roads Services Division before “owner will maintain” signs can be issued. Maintenance agreements should be received by the Road Services Division by March 31, 2008. The signs are once again being provided to property owners at no charge. The county has already sent letters to property owners who asked to maintain the right-of-way last year. Signs and copies of the maintenance agreement are available by calling (206) 296-8100 or toll-free by calling 1-800-KC-ROADS. The maintenance agreement is also available on the Road Services Division website. Residents who maintain their right-of-way are asked to place vegetation that may contain tansy ragwort or other regulated noxious weeds in sealable bags to prevent the spread of the weeds.

News from Neighboring Counties

Snohomish County Weed Board received prominent coverage in the Everett Herald when they voted to remove Canada and bull thistle from their noxious weed list, along with a few hawkweeds, due to limited budgets and rising costs.

Kitsap County Weed Board and a Bainbridge Island High School were featured in an article in the Kitsap Sun for their work removing invasive weeds at Blakely Harbor Park on Bainbridge Island.

National Conference on Community Based Weed Management

"People-Powered Projects: The National Cooperative Weed Management Area (CWMA) Conference" will be held April 15-17, 2008, in Reno, NV.  With representatives from all 50 states, the conference will focus on CWMA funding and logistics, working with volunteers, early detection/rapid response (EDRR), awareness and outreach, state and national initiatives, and will conclude with an all-day field trip to sites in the Reno area.

Cooperative Weed Management Areas mobilize communities to prevent and manage invasive plants and to support healthy ecosystems. Join CWMA workers, land managers, and concerned citizens in a national conference to learn from each other, improve approaches to CWMA organization and management, and increase support for CWMAs across the United States.

The event is organized by the Center for Invasive Plant Management and co-hosted by the Midwest Invasive Plant Network, Invasive Plant Atlas of New England, Cal-IPC, Alaska CNIPM, Mid-Atlantic EPPC, Southeast EPPC, and the Nevada Dept. of Agriculture. For more information, visit the Center for Invasive Plant Management website.

Cricket Fans Accidentally Learn About Noxious Weeds

A big spike in visits to the Noxious and Obnoxious Weeds page on our website had us scratching our heads a few weeks ago. We found out that the unlikely cause of this was two cricketers – Australian Matthew Hayden and Indian Harbajhan Singh – trading insults in the heat of an international cricket match in Sydney. Hayden called Singh an “obnoxious little weed”. This resulted in a media firestorm and thousands of hits on the program’s obnoxious weed page on our website. Apparently lots of Indians and Australians wanted to find out just what the insult meant. If you Google obnoxious weed, the top site is our web page. So inadvertently we are educating Indian and Australian cricket fans about weed control.

King County Website Update

The domain name for all of King County’s websites is changing from metrokc.gov to kingcounty.gov by the end of 2008. We have a quick link set up for our home page: www.kingcounty.gov/weeds but we don’t have the addresses for the other pages yet. As the transfer moves forward, the links in this newsletter and earlier additions may not work, but the main address above will continue to work and you can always navigate to the individual pages from the index page. Hopefully this will not cause too much of an inconvenience. Please feel free to contact Sasha Shaw (206-263-6468) if you encounter any problems with accessing our website.

Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact a staff member at the King County Noxious Weed Control Program, please call 206-296-0290 or by reach them by email.

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