KC Weed News - August 2005
 Topics Below
Weed of the Month: Garden Loosestrife, Class B Noxious Weed
If you happen to walk along the boardwalk at Marymoor Park this time of year, it will be hard to miss the masses of bright yellow flowers on one of the most challenging noxious weeds we have in this county. Garden loosestrife (Lysimachia vulgaris) was introduced to North America from Europe as an ornamental in the 1900’s and is now naturalized in wetlands and lakeshores in parts of the northwest, midwest and eastern United States and Canada. Garden loosestrife displaces native vegetation along streambanks, wetlands and shorelines and reduces habitat needed by waterfowl and fish, including several important salmon species.
Although garden loosestrife hasn’t been in our county as long as purple loosestrife, it is slowly building up steam in our part of the world and is even out-competing purple loosestrife in some areas. Once garden loosestrife establishes in an area, it spreads by creeping roots called rhizomes that seem to extend forever and create dense, underground mats that are extremely difficult to remove. King County has more garden loosestrife than anywhere else in our region and most of it is growing around Lake Sammamish, Lake Washington and the Sammamish River, although smaller populations have also been found in a wetland near the Snoqualmie River and around Lake Burien. In 2004, we recorded 94 sites with garden loosestrife, covering 6.7 acres. We have just begun to map all the properties along Lake Sammamish and Lake Washington, so we expect that number to be even higher this year.
In the past, we have focused on controlling outlying infestations of garden loosestrife and we continue to work away at those populations. Also, starting this year, we will be increasing our efforts on the heart of the infestations along the two big lakes and Sammamish River. The largest infestations are along public lands so we are working with those agencies to develop a plan of action for these sites. We have also begun educating lakeside and riverside property owners about this plant and asking them to cut down plants before they go to seed.
Identifying garden loosestrife (also known as yellow loosestrife) can be confusing, especially by its name. First, although it shares habitat and invasive tendencies with purple loosestrife (Lythrum salicaria), it looks very different and is not even related to this other noxious wetland invader. Also, garden loosestrife has a closely related look-alike also known as garden or yellow loosestrife (Lysimachia punctata) that is often used as an ornamental in this area. Both have bright yellow 5-petaled primrose-like flowers on tall, softly hairy stems. However, the noxious garden loosestrife has branched flowering stems with flowers clustered near the top of the plant (not just in the leaf axils), less than ½ inch wide, with distinct orange margins along the edges of the sepals, and it is more likely to be found in wetlands than gardens. Garden loosestrife is easiest to identify when it flowers in July and August.
If you have any concerns about tansy ragwort or find any new infestations, please contact us at noxious.weeds@kingcounty.gov or use our online form.
One of our primary missions is to find early infestations of noxious weeds while it is still possible to stop them from impacting our county. Thanks to the sharp eyes of Noxious Weed Specialist Karen Peterson, we found a small infestation of the noxious weed hairy willowherb (Epilobium hirsutum) in the wetlands of the University of Washington-Bothell campus. This tall, attractive but highly invasive European cousin of fireweed escapes cultivation to form monotypic stands in natural wetland areas, where aggressive and dense growth can crowd out native or beneficial species. This species is established throughout most of the northeastern United States and it continues to spread westward. Most of the known infestations in Washington are in Whatcom County but it is known from other counties as well. There have been reports of hairy willowherb in King County but the UW-Bothell infestation is the first time our program has come across this plant. Because hairy willowherb threatens wetlands as much as purple and garden loosestrife, it was designated as a Washington State Class C Noxious Weed in 2004 and the King County Noxious Weed Board selected it for required control based on the level of potential damage it could do and the fact that we hadn’t found any infestations yet. We are very interested in locating any other populations of this plant, so we ask everyone to keep an eye out for it. The flowers are very showy and noticeable in July and August and the seed pods look just like fireweed. Check out the following links for pictures and more information.
http://www.co.whatcom.wa.us/publicworks/pdf/weeds/aquatic/hairy_willow_herb.pdf
http://www.nwcb.wa.gov/weed_info/Written_findings/Epilobium_hirsutum.doc
http://www.ecy.wa.gov/programs/wq/plants/weeds/willowherb.html
http://www.plant-identification.co.uk/skye/onagraceae/epilobium-hirsutum.htm
Aquatic Weed Control Permits: NPDES Troubles
If you need to use herbicides to control aquatic noxious weeds, then you probably know (or should know) about the NPDES permit. This is required for any application of herbicide to surface waters in Washington (and generally for any discharge of pollutants into waters of the state). The permitting agency is Washington State Department of Ecology and it is not an easy process to go through. Fortunately, Washington State Department of Agriculture (WSDA) has a permit from Ecology to apply herbicides to control noxious weeds throughout the state and they are able to cover public and private applicators through a streamlined and no-cost application process with a short seven-day turn around (http://agr.wa.gov/plantsinsects/weeds/npdespermits/default.htm).
Unfortunately, this year, due to an ongoing lawsuit related to WSDA’s permit, this blanket coverage has not been available in some cases for private contractors and landowners. WSDA will still be providing NPDES coverage to private contractors and landowners for freshwater emergent applications (e.g., purple loosestrife, garden loosestrife, yellow flag iris). However, coverage for the submersed and floating species in lakes will only be granted to governmental entities (e.g. watermilfoil, Brazilian elodea, water lilies). A private contractor can still apply for NPDES coverage for lakes directly from Ecology and pay the permit fees but the turn around time and the costs of doing this directly may be out of reach for many private contractors. This has caused considerable problems for lakeside property owners, marinas and other lake users who may not be able to keep their aquatic weeds in check this year. For next year, the Department of Ecology is working on a permit for lakes that will be more streamlined and less expensive, but that is still in the works. Also, although public agencies (including our program) are still able to get NPDES coverage for submersed and floating weeds, according to our legal council, we cannot give coverage to third parties for aquatic weed control. This leaves manual and mechanical methods as the tools available for private contractors for controlling floating and submersed weeds. For information about aquatic weeds and control methods, please see the Ecology website: www.ecy.wa.gov/programs/wq/links/plants.html.
Noxious Weeds in the News: Links to Recent Articles
Thanks in part to the really amazing show of tansy ragwort this year, the weed world has been getting some publicity in our region. Here are links to some of the articles that have come out locally and a few from farther away:
http://seattlepi.nwsource.com/local/233843_gcenter25.html
http://dwb.thenewstribune.com/news/projects/thepark/story/5045981p-4601536c.html
www.king5.com/localnews/environment/stories/NW_061805ENBinvasiveplantsKC.20634138.html
Upcoming Educational Opportunities
The noxious weed program holds free public workshops on invasive plants and noxious weed management mostly in the spring and early summer. After several months of workshops, the outreach program will be taking a short break. Watch for announcements on upcoming workshops in future months.
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