KC Weed News - January 2010Topics Below 
Weed of the Month: English Laurel (Prunus laurocerasus), Weed of Concern in King County, Washington While researching this month’s featured plant, I discovered that English laurel (Prunus laurocerasus) is not in fact from England or anywhere else in the United Kingdom, but rather from the region around the Black Sea in southeastern Europe and southwestern Asia. Perhaps ironically given the name, the most detailed information I could find on controlling English laurel came from a website out of Ireland. It appears that the worst woody invader in Ireland is the purple-flowered Rhododendron ponticum (the only Rhododendron I know that is so invasive). However, it seems that English laurel (or cherry laurel as it is usually called in England) is not far behind. Both form dense impenetrable thickets in Ireland’s woodlands and both are tough to control. Here in the Pacific Northwest, you may be more familiar with this plant as a fast-growing hedge, often growing taller and wider than the space where it was planted, but generally appreciated as useful hedge plant with densely packed glossy leaves. However, when it is allowed to produce fruit, birds carry the seeds into wooded areas, where it grows into small trees with large, spreading limbs covered with dense foliage. Because it is evergreen, English laurel grows well in our year-round mild climate, and because it grows quickly in all sorts of conditions and produces tons of seedlings, English laurel can quickly dominate the shrub and small tree layer once it gets a foothold. In our urban forests, where English laurel is becoming especially common, it is joining English holly in out-competing and replacing native evergreen trees such as hemlock, cedar and Pacific yew, that would normally be re-generating in the understory of our forests. Even in more remote areas of the county, it is not unusual to see English laurel growing in the wild. Last year, on a walk in the Middle Fork Snoqualmie natural area in the foothills of the Cascades, we found a few English laurel trees growing in the woods near some other ornamental escapees, probably spread from an old residence or yard waste dump site. English laurel is not considered a noxious weed in Washington and it is completely legal to buy and sell it in the state. However, in King County we have given it Weed of Concern status because of how invasive it is and because of the potential threat to the long term health of our native forest communities. Although not nearly as widespread as English holly in rural King County, it is almost as difficult to control and it is clearly a serious problem in many urban forests. I wonder if it isn’t as widespread as holly partly because it is usually pruned as a hedge and not allowed to fruit as much as holly (which we grow in part for the bright red berries). However, there are plenty of wild, fruiting English laurel trees now in the urban parts of the county and it is probably only a matter of time before we start seeing more escapees throughout the county. There are many other great hedge plants to use instead of English laurel, most of which won’t have such rapid, overwhelming growth (remember, English laurel wants to be 20 feet tall and will grow back quickly every time you cut it!). One native evergreen shrub that makes a lovely hedge is evergreen huckleberry, with the added bonus that the berries are tasty and make great jam (English laurel fruits are only tasty for birds and can be poisonous). For more information on this and other native plants that work as hedges, check out King County’s Native Plant Guide and search with the key word “hedge”. If none of these work for you, any local nursery can provide many great suggestions for alternatives to English laurel. Just make sure to ask for something non-invasive (it would be a shame to avoid one problem, only to get something just as bad!). For more information on English laurel, check out our website or contact us at 202-296-0290 or noxious.weeds@kingcounty.gov. Weed Tips for JanuaryPull over-wintering weeds now while the soil is soft and moist. Rosettes of weeds like knapweed, tansy ragwort, garlic mustard, milk thistle, and poison-hemlock are pretty easy to find now and the roots will come out without breaking, especially if the weather stays reasonably warm. While the soil is moist and there’s not much growing out there, it’s a great time to find and pull these and other over-wintering noxious weeds. Scotch broom pulling is a great winter project. Not only is it very easy to find scotch broom with its evergreen stems, it is easier to pull in moist soil and you are less likely to damage roots of nearby plants. Unlike blackberries, Scotch broom doesn’t have thorns and so makes for an easy work party activity if you can get a few weed wrenches for people to use. Often parks departments have weed wrenches available for work parties on public lands. If you need a weed wrench for your own property, you can borrow one of ours for a week or two. Just contact us at 206-296-0290 or by email to reserve a time and then come to our office in Seattle at 201 S. Jackson, 6th floor (next to the train station) to pick it up.
Mulch before the weeds pop up. If you have ever struggled with garden beds full of pesky annuals like bittercress a.k.a. shotweed (Cardamine hirsuta and related species), then mulching now might be your answer. Bittercress is happily growing right now, undeterred by the winter chill, and will be bolting and seeding before you know it in the early spring. There are many other annual weeds that can be managed well by a nice thick layer of mulch in garden beds and any areas that lack good plant cover to keep the weeds in check. Get rid of invasive tree stumps before they start to re-grow. If you’ve spent your winter cutting down invasive trees and didn’t treat the cut stumps with herbicide, you might find yourself with a lot of new growth in a few months. If so, you might want to think about removing the stumps while the ground is still pretty soft. If you haven’t already done the cutting, make sure to leave a good sized stub on the stump for leverage (up to 4ft high) rather than cutting it off at ground level. Grubbing out the roots with a shovel is slow, hard work but it is usually possible to remove the majority of the root ball, at least for small trees. Remove and loosen dirt around the main lateral roots and as deep as possible, cut off deep or stubborn roots with a hand saw as far down as possible, then pull out the main root ball. Another option is to rent a mechanical mini-excavator to help with the digging or pull the root ball out with a winch. If you are unsure about doing this yourself, you can hire a landscape contractor. Root balls can be turned upside down and left in the woods if you have room. Otherwise they will need to be hauled off to the transfer station. Hiring a contractor with a stump-grinder is another option, although it can be somewhat expensive. This grinds the main root into sawdust. Some roots will inevitably be left in the ground, but the majority should eventually rot down, and you are left with sawdust to use as mulch somewhere else or just leave in place. It is recommended to grind at least 8-10 inches down if you are putting in turf or about 12 inches down if you are re-planting. Washington State Weed Board to Consider Rule Changes at January 11 Public HearingOn January 11, the State Weed Board is holding a public hearing on two proposed changes to the Chapter of the Washington Advisory Code (WAC) that contains the state weed list and other rules about noxious weed control in Washington (WAC 16-750). The first proposed change is a clarification of what it means to “control” noxious weeds. The second limits the per-day penalty for failure to control the listed weeds to a maximum of five days.
The public hearing will be held from 11 AM to 1 PM on Monday, January 11 in Room 175 of the Natural Resources Building at 1111 Washington Street in Olympia. The purpose of the public hearing is to solicit citizen comments and opinions about the proposed rule changes.
Those who wish to comment on the proposed changes may do so orally at the public hearing, or by submitting written testimony, which can be emailed to ahalpern@agr.wa.gov or mailed to WSNWCB, PO Box 42560, Olympia, WA 98504. Written testimony must arrive no later than 5 PM Monday, January 11, 2010.
The Board will vote on the proposed rule changes during its regular meeting on Tuesday, January 12 beginning at 9 AM in the Lookout Conference Room in Office Building Two at 1115 Washington Street in Olympia. This meeting is also open to the public.
The first change, relating to the definition of “control,” (WAC 16-750-003(2a)) simplifies the definition and eliminates technical language. Currently, “’Control’ means to prevent all seed production and to prevent the dispersal of the following propagules of aquatic noxious weeds – turions, fragments, tubers, and nutlets.” The proposed text would read “’Control’ of noxious weeds means to prevent all seed production and to prevent the dispersal of all propagative parts capable of forming new plants.” The intent of the change is to simplify the rule, in keeping with the Governor’s Executive Order requiring plain language that can be understood by those required to comply with state rules.
The second change limits the penalties to property owners who fail to control or eradicate noxious weeds following notice by local authorities that they must do so. In the current WAC, (WAC 16-750-020(1)) there is no limit on the per-day penalty; the proposed change limits the penalty to a maximum of five days.
For more information about the Washington State Noxious Weed Control Board, and for the full text of laws and rules governing noxious, invasive weeds, please go to www.nwcb.wa.gov. County Weed Board to Decide on King County’s 2010 Weed List The annual King County Noxious Weed List Hearing will be held at the January 20 King County Weed Board Meeting (Mercer Island Library, 4 pm to 6 pm, small conference room). The public is invited to attend. The Board will consider any proposals presented about plants listed on the 2010 State Noxious Weed List and then formally adopt the King County Noxious Weed List for 2010. County weed boards are required to include all state Class A and state-designated Class B weeds on the county list (see the State Weed Board website for the current weed list and county designations). In addition, the county board can select additional Class B and Class C weeds from the state list for the county list and may require property owners to control these species in part or all of the county (see the King County Weed List for information on the current county list and selected control areas). This year there are no new species on the state weed list and there have been no proposals for new county weeds of concern. The only change currently being proposed is to move one species, absinth wormwood (Artemisia absinthium), from the non-regulated noxious weed list to the regulated noxious weed list, with control required county-wide. Absinth wormwood is mostly limited in distribution in our county to highway shoulders, a few county roads, and railroad rights-of-way. However, it is regularly re-introduced from eastern Washington by way of the highways and could potentially become a much bigger problem in King County. Once this plant gets established in a pasture or range area, it is very difficult to remove and can have significant impacts on the quality of forage for wildlife and livestock. There are several species of wormwood found in King County as well as a few other look-alikes, so it is important to get a positive identification before controlling. For more information, visit our website or contact us at 206-296-0290. In addition to this change, the County Weed Board will review the existing list and decide on whether to continue the existing county selections. These include: Continue to require control county-wide of the following Class B weeds: tansy ragwort ( Senecio jacobaea), purple loosestrife ( Lythrum salicaria), and garden loosestrife ( Lysimachia vulgaris). Tansy ragwort is not designated by the State Weed Board for required control in King County. Purple and garden loosestrife are state-designated only outside of the most densely infested areas. The County Weed Board has chosen to require control of all three species county-wide in previous years. Continue to require control county-wide of the following Class C weeds: hairy willowherb ( Epilobium hirsutum), common hawkweed ( Hieracium lachenalii), and unspecified non-native invasive hawkweeds ( Hieracium sp.) Continue to require control of Scotch broom ( Cytisus scoparius) along I-90 from mile marker 34 to the King/Kittitas County line and along the King County section of SR 2, in order to provide a buffer for neighboring counties, but keep it on the list of non-designated noxious weeds for recommended control elsewhere in the county. Continue to require control of invasive knotweeds ( Polygonum spp.) on the sections of the Green River and tributaries where we have achieved good control through our externally funded projects in order to sustain that level of control for that system. The language on this would remain the same as last year (see the Non-Regulated Noxious Weed List)
The County Weed Board welcomes public input and comments are encouraged. If you have any proposals or comments, contact Steve Burke at 206-205-6927 or feel free to attend the public meeting on January 20.
State Budget Cuts May Eliminate State Weed Board and Change Weed Listing Process In the budget proposal released by the Governor on December 9, one of the reductions included is the elimination of the State Noxious Weed Board and its $85,000 budget. As the proposal stands, Washington State Department of Agriculture (WSDA) would assume responsibilities for implementing the State Noxious Weed Law (RCW 17.10) as well as deciding on the annual state noxious weed list and related rules (WAC 17-650). The details of how the weed listing process would change are not completely known at this time. The proposed budget also reduces the state spartina and knotweed control grant programs by $33,000 and $108,000 respectively. The state legislature will be considering these cuts along with the rest of the state budget during the current session. Details about the proposed budget recommendations for WSDA are available here: http://www.ofm.wa.gov/budget10/recsum/495.pdf. Details about the proposed supplemental budget and its impact on other programs and agencies are available here: http://www.ofm.wa.gov/budget10/recsum/default.asp, and the Governor’s press release is here: http://www.governor.wa.gov/news/news-view.asp?pressRelease=1391&newsType=1. For more information, contact Alison Halpern, executive secretary for the Washington State Weed Board or Steve Burke, here at the King County Noxious Weed Control Program.
Flower and Garden Show is Here Again Last year we worried that we would no longer have this lovely antidote to our grey winters, but thankfully the Pacific Northwest Flower and Garden Show is alive and well once again. It will be held a bit earlier this year, from February 3 to 7, at the Convention Center in downtown Seattle. When you’re browsing the booths in the vendor section, make sure to stop by the WSDA-Noxious Weed Board booth and the King County Department of Natural Resources and Parks booth. There will be noxious weed experts on hand at the state noxious weed table and plenty of great gardening and weed resources at both booths.
County Agencies Deliver on Noxious Weed Control in 2009 Despite Challenges In a year filled with serious challenges such as declining budgets and staff layoffs, several county agencies showed great tenacity and dedication in their noxious weed control efforts. As a result, most regulated noxious weeds on county-managed lands and roadsides were controlled. Most notably, Road Services and Stormwater Services staff did an exceptional job this past weed season. Road Services’ vegetation specialists were in constant contact with us at the King County Noxious Weed Control Program confirming control of noxious weeds that our staff notified them about. And, by doing excellent control work at their first visit, they greatly reduced the need for repeat visits and inspections by our staff and theirs, saving precious time and money for everyone. Roads staff also identified and controlled many new noxious weed sites on their own initiative while conducting other maintenance duties, and made it a point to notify us about these locations so they can be monitored in proceeding years. Stormwater Services also did a notable job this past season despite challenges such as budget concerns, an increase in the number of facilities where noxious weeds were found, and newly identified species that their staff were unfamiliar with and had never controlled before. By strategically using more cost-effective methods where possible and applying good IPM principles, they were able to control all sites that we notified them about. And, instead of waiting for us to follow up when they were faced with new weeds or questions about locations, their staff contacted us to ask for more detailed information on locations and identification and control methods for the new weeds. By being proactive and strategic, Stormwater Services staff saved time and money for their staff and ours and were able to achieve really good weed control results at the same time. Overall, on county-managed properties and roadsides, the most abundant noxious weed found in 2009 by far was tansy ragwort with 875 sites on roads and parcels. Other upland weeds that were fairly abundant included sulfur cinquefoil, several species of hawkweed (yellow, orange, European, common and mouseear), and spotted, meadow and diffuse knapweed. Some of the less common upland weeds found were milk thistle, giant hogweed, goatsrue, Dalmatian toadflax, policeman’s helmet, gorse, viper’s bugloss (blueweed), rush skeletonweed, perennial pepperweed, perennial sowthistle and leafy spurge. Wetland plants found were purple loosestrife, garden loosestrife, common reed and, in one location each, hairy willow-herb and floating primrose-willow. For information on these and other noxious weeds found in King County, visit our weed index page. There are currently 382 known regulated noxious weed sites on county-managed parcels. In 2009, our staff were able to survey 269 of those sites and control was achieved on 241 (90 percent) of those sites. Our staff also surveyed over 400 county roads and identified 982 regulated noxious weed sites along county roads. Control was confirmed on 965 (98 percent) of these sites. The majority of the control work was done by the county agency responsible for managing the land or roadside, but our staff helped out with some of the more difficult sites and with follow-up control on skipped plants, as well as helping with identification and choosing the best control methods. This team effort went a long way to holding back the tide of noxious weeds on county lands and we look forward to building on this progress in 2010.
Brazilian Elodea Continues to Spread, Even in Winter Brazilian elodea (Egeria densa) is on the move. This submerged class B noxious weed was already known from several places in the county’s big lakes, Washington, Sammamish and Union, and a survey in August last year found it almost bank to bank in parts of the Sammamish River. Then, in October, an alert citizen reported four acres of it in Seattle’s Fisherman’s Terminal – and it hasn’t died back despite December’s deep freeze. It is so thick in places that a sailboat had to be towed out of its slip because the weeds were stronger than the boat motor and kept the boat from moving. Improper disposal of unwanted aquarium plants was likely the pathway for introduction of Brazilian elodea into the Lake Washington system in the first place, and it is possible that there have been multiple introductions over the years. Although it is illegal to buy or sell this plant in Washington according to the state quarantine rule (WAC 16-752-500), there is an exception allowed for research and educational use. Recently, at least two school districts in the county used this exception to purchase Brazilian elodea for use in classrooms. The problem with this comes when it is time to dispose of the plant material. Even a small amount of this plant can grow into a new infestation when discarded in a lake or stream. Hopefully most teachers will follow instructions on proper disposal, but unfortunately not all will do so. Indeed, this fall, we received a report of a teacher who sent the Brazilian elodea home with students despite warnings about the invasive nature of the plant. Well-intentioned children may well decide to release the plants “back into the wild”. A nice thought but not a good action in the case of invasive species like Brazilian elodea. The moral to this story – don’t dump unwanted aquarium plants or animals (or any other living thing) into natural waterways. You never know what might survive to be the next big invader!
Invasive Species in the NewsNOTE: To receive KC Weed News by email, contact Sasha Shaw.
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