Tag Archives | noxious

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Woody Weeds of Clackamas County

A New WeedWise Publication The WeedWise Program is pleased to announce a new publication entitled, Woody Weeds of Clackamas County.  This resource guide is intended for use by local landowners and land managers to help them identify and manage woody weeds and naturalizing plants on their property. The Woody Weeds of Clackamas County covers a […]

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Goatsrue Eradication Project

Since 2016, the WeedWise program has been working to control the largest known infestation of goatsrue (Galega officinalis) in Oregon. Goatsrue is an Oregon class A noxious weed and has been deemed a high priority for control and eradication because it is toxic to livestock and spreads easily.  This federal and state noxious weed is only known at a handful of other sites across Oregon and the Pacific Northwest.

Goatsrue flowers

About Goatsrue

Goatsrue is a deep-rooted perennial, with hollow stems and compound alternate leaves.  The compound leaves have a terminal leaflet and 6-10 pairs of leaflets. The tip of each leaflet rapidly narrows to a fine tip. Goatsrue has pea-like flowers that vary in color from purple to white. Flowers bloom from June to October and are clustered at the end of its branches or at the leaf axils. Unlike some other members of the pea family, goatsrue lacks tendrils and grows in a more upright and bushy form rather than as a vine. The seeds are contained in pods with up to 9 mustard-colored, oblong seeds. Each plant can produce 15,000 pods a year. Additionally, these seeds may remain viable for 5-10 years in the soil.

Goatsrue closely resembles some regionally rare native plants, so we encourage landowners to contact us if they think they may have goatsrue on their property.

Robust goatsrue growth

What we Found

In May of 2016, during one of our planned weed surveys, one of our contracted survey crews discovered a large previously unknown population of goatsrue on two adjacent riparian properties along the Clackamas River. This infestation affects 14 acres and is the largest known infestation of goatsrue in Oregon. At that time, we began a management effort to contain and control this priority weed with the goal of eradication of the goatsrue as well as several other priority invasive plants present at these sites.

This discovery was found as part of extensive surveys of streamside properties along the Clackamas River initiated in 2015 and continuing into the present. Twenty-one priority invasive plant species were on our target list for these surveys. Some of these species had been documented in our region and some had not. These surveys help us to address new priority invasive plants and better manage priority invasive plants established here. We thank private landowners for allowing us to access their properties for these surveys!

Goatsrue herbicide application

What we are doing

The WeedWise Program initiated control soon after detection of this large infestation. Our approach began confirming the identity of the goatsrue. We then followed up with a thorough review of the biology and control of goatsrue. Most notably, we learned that goatsrue can have a long seed dormancy period allowing seeds to grow after 10 years in the soil. As a perennial weed with a deep taproot, it is all difficult to remove by hand. Therefore, our management goals were to prevent all seed production and to target the large root systems of existing plants.

Next, we researched management strategies appropriate for this plant and this site. We also consulted with the Oregon Department of Agriculture Noxious Weed Control Program and the City of Portland Bureau of Environmental Services who both have prior experience managing goatsrue. Based on this research, we selected two herbicides to treat the infestation: one to target upland populations and a second aquatically approved herbicide to treat infestations that occur near water. The herbicide applications were planned by the WeedWise program and implemented using licensed restoration contractors.

What’s Next?

To date, our management efforts have been highly successful, but with the size and complexity of the site we did note some patches with regrowth after herbicide application, as well as new seedlings emerging. On follow-up monitoring of the site, we also found several overlooked patches that had grown in an among other vegetation. In response, our current efforts focus on continuing to scout for missed populations and to remove interspersed invasive Himalayan blackberry (Rubus bifrons) stands which may obscure goatsrue plants. We are carrying out multiple rounds of control each year to ensure that we are not letting any plants go to seed and to continue to address regrowth.

After two years of intensive control, we have dramatically reduced the populations and are on track to eradicate this population. Eradication will require ongoing monitoring and control to address the long seed dormancy. Although we won’t be walking away from the site anytime soon, we are optimistic knowing that the population is significantly reduced, and that we are committed to eradicating goatsrue from Clackamas County!

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January’s Weed of the Month!

Our first 2017 weed of the month is ivy! You’ve probably seen it carpeting the ground in a natural area, or perhaps completely covering a wall, or possibly climbing high up a tree. Like many invasive plants, it was introduced as an attractive ornamental plant for landscaping. However, it escaped! Ivy has become highly invasive […]

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December’s Weed of the Month!

Deck the Halls with Boughs of Holly! December is the month when our busy lives get busier. The December mad dash of shopping, baking, wrapping, and mailing, ultimately gives way to the holidays spent surrounded by our loved ones. December should be a time of enjoying each others company, not concerning ourselves with weeds. After […]

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Working Together

The old adage “many hands make light work” could not be truer when it comes to weed management. The WeedWise Program routinely works with a number of partnering entities and organizations across our region to combat invasive weeds.  This include local, state, and federal agencies as well local non-profits and watershed councils. Our partnerships also […]

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Purge the surge in spurge!

This past season we have seen a rise in the number of Oblong spurge (Euphorbia oblongata) sites appearing in Clackamas County.  Oblong spurge is a class A noxious weed in the state of Oregon, and eradication of this species is required across the state.  It is known to be highly aggressive and can displace native […]

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WEEDS

What are weeds?

There are a whole host of terms to describe weeds.  The term “weeds” itself can refer to any plant that occurs in an undesirable location. Terms like “non-native“, “exotic“, “alien” or “non-indigenous” refer to plants that occur in areas where they historically did not occur.  These terms make no distinction whether plants are desirable or undesirable.  The term “invasive” refers to a plant or animal that exhibits aggressive growth and displace other species.  Other terms like “noxious” or “nuisance” refer to plants that have special designation by the state or by a municipality the prohibits their sale or cultivation.  With this broad diversity of terms, it is no wonder that many people find themselves confused and wondering how to make sense of it all.

At the WeedWise program, we hope to clarify this issue by focusing on plants we refer to as “invasive weeds”Invasive weeds are plants that live outside their historic geographical range, and whose aggressive growth habit has a detrimental effect on our social, economic, or ecologic resources.  The three key components of invasive weeds are that they:

  1. Did not historically occur in our area, but have been brought in either intentionally or unintentionally through human action.
  2. Exhibit aggressive growth which displaces native or desirable vegetation, and will continue to spread unless actively controlled.
  3. Have a negative impact on our community.

These three characteristics clarify invasive weeds as those plants that pose the greatest threat to our community.  By focusing on invasive weeds the WeedWise program is working to maximize its limited resources to realize the greatest benefit to Clackamas County.

Defining our priorities

All invasive weeds pose a major threat to the residents of Clackamas County, but some of these pests can be more damaging than others.  In addition, the costs to control these invasive weeds greatly exceeds the resources available for their management.  As a result, the WeedWise program has prioritized its efforts to target invasive weeds that pose the greatest risk, have the greatest negative impact, and may still be limited enough in their distribution to allow for eradication or containment in Clackamas County.  For these “priority” invasive weeds, the WeedWise program may have resources available to assistance Clackamas County landowners to control or manage these weeds.  For more common invasive weeds, the WeedWise program offers technical information and consultations to improve your efforts and to make your management practices more effective.

WeedWise Classifications

Priority:  These weeds are the highest priority and are actively being targeted for eradication by the WeedWise Program.  Landowners are encouraged to notify the WeedWise program for assistance with these weeds and to actively control them on their property.
Maintenance:  These weeds are damaging and widespread.  The WeedWise Program encourages control by landowners and can assist with the development of a plan to control these weeds.

Clackamas Weed List

Common NameScientific NameWeedWise ClassificationOregon ClassificationWashington Classification4-County CWMAColumbia Gorge CWMA
VelvetleafAbutilon theophrastiBBBB
Barbed GoatgrassAegilops triuncialispriorityA,Tnot listedAW
Tree of HeavenAilanthus altissimamaintenanceBCBC
Garlic mustardAlliaria petiolatapriorityB,TABA
False indigo bush Amorpha fruticosaBBnot listedB
Wild chervilAnthriscus sylvestrismaintenancenot listedBnot listedB
Italian arumArum italicummaintenancenot listedCBB
False bromeBrachypodium sylvaticumpriorityBABA
Butterfly bushBuddleja davidii (Buddleja varabilis)maintenanceBBBB
Flowering rush Butomus umbellatuspriorityA,TAWA
Welted thistleWelted thistlepriorityA,Tnot listednot listednot listed
Drooping sedgeCarex pendulapriorityWnot listedWB
Meadow knapweedCentaurea × moncktonii (C. pratensis)maintenanceBBBB
Spotted knapweedCentaurea stoebe (C. maculosa)maintenanceB,TBBB
Rush skeletonweedrChondrilla junceapriorityB, TBDB
Canada thistleCirsium arvensemaintenanceBCCC
Bull thistleCirsium vulgaremaintenanceBCDC
Old man's beardClematis vitalbamaintenanceBCBC
Poison hemlockConium maculatummaintenanceBBBB
English hawthornCrataegus monogynamaintenancenot listedCCC
Yellow nutsedgeCyperus esculentusmaintenanceBBBB
HoundstongueCynoglossum officinalepriorityBBDB
Scotch broomCytisus scopariusmaintenanceBBCB
Wild carrot Daucus carotamaintenancenot listedCCC
Spurge laurelDaphne laureolapriorityBBBB
Common teaselDipsacus fullonummaintenancenot listedCCC
South American waterweedEgeria densamaintenanceBBCB
Myrtle spurgeEuphorbia myrsinitesmaintenanceBBEB
Oblong spurgeEuphorbia oblongatapriorityA,TAAA
GoatsrueGalega officinalispriorityA, TAAA
Shining geraniumGeranium lucidummaintenanceBBBA
Herb robertGeranium robertianummaintenanceBBCB
English ivyHedera helixmaintenanceBCCB
Irish ivyHedera hibernicamaintenanceBCCB
Giant hogweedHeracleum mantegazzianumpriorityA, TAAA
Orange hawkweedHieracium aurantiacumpriorityA,TBAA
Meadow hawkweedHieracium caespitosumpriorityB,TBAB
St. John's wort Hypericum perforatummaintenanceBCCC
Hairy cat's earHypochaeris radicatamaintenancenot listedCCC
JewelweedImpatiens capensismaintenanceWCCW
Policeman's helmet Impatiens glanduliferapriorityBBBB
Yellow flag irisIris pseudacorusBCBB
Yellow archangelLamium galeobdolonmaintenanceBBBB
Large-flowered primrose willowLudwigia grandifloramaintenanceB, Tnot listednot listedB
Primrose willowLudwigia hexapetalamaintenanceB, TBnot listedB
Water primroseLudwigia peploides ssp. montevidensismaintenanceB, TAAA
Purple loosestrifeLythrum salicaria priorityBBBB
Fragrant water lilyNymphaea odoratanot listedCDC
Small broomrapeOrobanche minormaintenanceBnot listedDA
African ruePeganum harmalapriorityA,Tnot listedAW
Japanese butterburPetasites japonicanot listednot listedWB
American pokeweedPhytolacca americanaWnot listedBA
RibbongrassPhalaris arundinacea var. pictamaintenanceB,T Cnot listedC
Reed canarygrassPhalaris arundinaceamaintenanceWCnot listedC
Bohemian knotweedFallopia × bohemica ( Polygonum × bohemicum )priorityBBCB
Japanese knotweedFallopia japonica ( Polygonum cuspidatum )priorityBBBB
Giant knotweedFallopia sachalinensis ( Polygonum sachalinensis )priorityBBBB
Curly-leaf pondweedPotamogeton crispusmaintenancenot listedCCC
Sulphur cinquefoilPotentilla rectapriorityBBAB
KudzuPueraria montanapriorityA,TAAA
Lesser celandineRanunculus ficariamaintenanceBBBB
Armenian (Himalayan) blackberryRubus armeniacus (R. bifrons, R. procerus, R. discolor)maintenanceBCCC
Evergreen blackberryRubus laciniatusmaintenancenot listedCCC
Tansy ragwortSenecio jacobaeamaintenanceBBBB
Common groundselSenecio vulgarismaintenancenot listedCnot listedC
Blessed milk thistleSilybum marianumpriorityBAAA
Perennial sowthistleSonchus arvensis ssp. arvensismaintenancenot listedCDC
Common tansyTanacetum vulgaremaintenancenot listedCCC
GorseUlex europaeuspriorityB,TBAA
Garden yellow loosestrifeLysimachia vulgarispriorityA,TBAW
Spiny cockleburXanthium spinosumpriorityBCDC
Syrian bean-caperZygophyllum fabagopriorityAAAA
Biddy-biddyAcaena novae-zelandiaeBnot listednot listedW
Russian KnapweedAcroptilon repenspriorityBBAB
Pheasant eyeAdonis aestivalispriorityBnot listednot listednot listed
Jointed goatgrassAegilops cylindricapriorityBCnot listedC
Ovate GoatgrassAegilops ovatapriorityAnot listedAW
CamelthornAlhagi pseudalhagipriorityABAA
BlackgrassAlopecurus myosuroidesnot listedCAW
Yellow tuftAlyssum corsicumpriorityA,Tnot listedAW
Yellow tuftAlyssum muralepriorityA,Tnot listedAW
RagweedAmbrosia artemisiifoliapriorityBnot listedDB
Skeletonleaf bursageAmbrosia tomentosapriorityAnot listedAnot listed
Annual buglossAnchusa arvensisnot listedBnot listedB
Common buglossAnchusa officinalispriorityB,TBAB
Absinth wormwoodArtemisia absinthiumnot listedCnot listedC
South African capeweedArtotheca calendulaWnot listednot listedW
Giant reedArundo donaxpriorityWnot listednot listedA
Common barberryBerberis vulgarisnot listedCnot listedW
Hoary allysumBertoa incanapriorityA,TBAB
White bryoniaBryonia albapriorityABAA
FanwortCabomba caroliniananot listedBnot listedW
Plumeless thistleCarduus acanthoidespriorityA,TBAA
Musk thistleCarduus nutanspriorityBBEB
Italian thistleCarduus pycnocephaluspriorityBADA
Slender-flowered thistleCarduus tenuifloruspriorityBADA
Smooth distaff thistleCarthamus baeticuspriorityAnot listedAW
Woolly distaff thistleCarthamus lanatuspriorityA,Tnot listedAW
Whitestem distaff thistleCarthamus leucocaulosWnot listednot listedW
Wild safflowerCarthamus oxyacanthaWnot listednot listedW
Longspine sandburCenchrus longispinusnot listedCnot listedC
Purple starthistleCentaurea calcitrapapriorityA,TAAA
Diffuse knapweedCentaurea diffusaBBBB
Iberian starthistleCentaurea ibericapriorityA,Tnot listedAA
Brown knapweedCentaurea jacea not listedBFB
Big-headed knapweedCentaurea macrocephalaWAnot listedA
Malta starthistleCentaurea melitensisnot listedBnot listednot listed
Black knapweedCentaurea nigra not listedBnot listedB
Vochin knapweedCentaurea nigrescensnot listedAnot listedA
Yellow starthistleCentaurea solstitialispriorityBBAB
Feather-headed knapweedCentaurea trichocephalaWnot listednot listedW
Squarrose knapweedCentaurea virgatapriorityA,Tnot listednot listedA
Oriental clematisClematis orientalisnot listedAnot listedA
Field bindweedConvolvulus arvensisB,TCCC
Jubata grassCortaderia jubatapriorityBCWB
Pampass grassCortaderia selloananot listedCnot listedC
Common crupinaCrupina vulgarisBAnot listedW
Smoothseed alfalfa dodderCuscuta approximataBCnot listedC
Bigseed dodderCuscuta indecoraBnot listednot listednotlisted
Japanese dodder Cuscuta japonicapriorityAnot listedAW
Five-angled dodderCuscuta pentagonaBnot listednot listednotlisted
Purple nutsedgeCyperus rotunduspriorityAnot listedAA
Portuguese broomCytisus striatusB,Tnot listedWW
Cape ivyDelairea odoratapriorityAnot listedAW
Cutleaf teaselDipsacus laciniatuspriorityBnot listednot listedW
Tree echiumEchium pininanaWnot listednot listedW
Paterson's curseEchium plantagineumpriorityA,Tnot listedAW
Viper buglossEchium vulgareWBnot listedB
Water hyacinthEichhornia crassipesWnot listednot listednot listed
Russian oliveElaeagnus angustifolianot listedCnot listedC
Hairy willow-herbEpilobium hirsutum not listedBnot listedB
Spanish heath Erica lusitanicaBnot listedWW
Toothed spurgeEuphorbia dentataWnot listednot listedW
Leafy spurgeEuphorbia esulapriorityB, TBBA
Common fennelFoeniculum vulgarenot listedBCB
French broomGenista monspessulanaBAWA
Reed sweetgrassGlyceria maximanot listedAnot listedA
BabysbreathGypsophila paniculatanot listedCnot listedC
HalogetonHalogeton glomeratuspriorityBnot listednot listedW
Texas blueweedHelianthus ciliarisnot listedAnot listedA
SpikeweedHemizonia pungenspriorityBCnot listedC
Yellow hawkweedHieracium × floribundumpriorityA,TBAA
Polar hawkweedHieracium atratumnot listedBnot listedW
Whiplash hawkweedHieracium flagellarenot listedBnot listedW
Queen-devil hawkweedHieracium glomeratumnot listedBnot listedW
Common hawkweedHieracium lachenaliinot listedBnot listedB
Pale hawkweedHieracium lactucellanot listedBnot listedW
Smooth hawkweedHieracium laevigatumnot listedBnot listedW
Spotted hawkweedHieracium maculatumnot listedBnot listedW
Wall hawkweedHieracium murorumnot listedBWW
Mouse-ear hawkweedHieracium pilosellapriorityA,TBAA
King-devil hawkweedHieracium piloselloidespriorityA,TBAA
European hawkweedHieracium sabaudumnot listedBnot listedW
HydrillaHydrilla verticillatapriorityAAWA
Common frogbitHydrocharis morsus-ranaepriorityAnot listedAW
Black henbaneHyoscyamus nigernot listedCnot listedC
Small-flowered jewelweedImpatiens parvifloraprioritynot listedAAA
Dyers woadIsatis tinctoriaBAnot listedA
KochiaKochia scopariapriorityBBnot listedB
Perennial peavineLathyrus latifoliusmaintenanceBnot listedCC
Lens-podded whitetopLepidium chalepensispriorityBnot listedAB
Hoary cressLepidium drabapriorityBCAB
Perennial pepperweedLepidium latifoliumpriorityB,TBAB
Hairy whitetopLepidium pubescenspriorityBCnot listedC
LepyrodiclisLepyrodiclis holosteoidesnot listedCnot listedW
Oxeye daisyLeucanthemum vulgaremaintenancenot listedCCC
West Indian spongeplantLimnobium laevigatumpriorityAnot listedAW
Dalmatian toadflaxLinaria dalmaticaB, TBBB
Yellow toadflaxLinaria vulgarismaintenanceBCBC
Rose campionLychnus coronariaWnot listednot listedW
Wand loosestrifeLythrum virgatum not listedBnot listedW
Scentless mayweedMatricaria perforatanot listedCnot listedC
Wild four o'clockMirabilis nyctagineanot listedAnot listedW
Variable-leaf milfoilMyriophyllum heterophyllumnot listedAnot listedA
Eurasian watermilfoilMyriophyllum spicatumpriorityBBCB
Hybrid watermilfoil Myriophyllum spicatum × M. sibiricum not listedCnot listednot listed
Parrots featherMyrophyllum aquaticummaintenanceBBBB
MatgrassNardus strictapriorityA,Tnot listedAW
Yellow floating heartNymphoides peltatapriorityA, TBAA
Scotch thistleOnopordum acanthiumpriorityBBAB
Taurian thistleOnopordum tauricumpriorityA,Tnot listedAW
Mile-a-minute weedPersicaria perfoliataWnot listednot listedW
Common reed Phragmites australis ssp. australispriorityBBAB
Hawkweed oxtonguePicris hieracioides not listedBnot listedB
Himalayan knotweedPolygonum polystachyumpriorityBBnot listedB
Austrian fieldcressRorippa austriacanot listedCnot listedC
Creeping yellow cressRorippa sylvestrisBnot listednot listedA
Sweet briar roseRosa rubiginosa ( R.eglanteria )Wnot listednot listedW
RavennagrassSaccharum ravennaepriorityAAAA
Grass-leaved arrowheadSagittaria graminea not listedBnot listedW
Delta arrowheadSagittaria platyphyllaAnot listedAnot listed
Mediterranean sageSalvia aethiopisBAnot listedA
Meadow clarySalvia pratensisnot listedAnot listedW
Clary sageSalvia sclareaWAnot listedW
Ricefield bulrushSchoenoplectus mucronatusWADA
Cereal ryeSecale cerealenot listedCnot listedC
White cockleSilene latifolia ssp. albanot listedCnot listedC
Silverleaf nightshadeSolanum elaeagnifoliumpriorityAAAA
BuffaloburSolanum rostratumpriorityBCDC
Sticky nightshadeSolanum sisymbriifoliumWnot listednot listedW
Field BurrweedSoliva sessilisnot listedCnot listedW
JohnsongrassSorghum halepensepriorityBAEA
Smooth cordgrassSpartina alterniflorapriorityA, TAAW
Common cordgrassSpartina anglicapriorityA,TAAW
Dense-flowered cordgrassSpartina densiflorapriorityA,TAAW
Saltmeadow cordgrassSpartina patenspriorityA,TAAW
Spanish broomSpartium junceumpriorityBAFA
SwainsonpeaSphaerophysa salsulaBCnot listedC
Water soldiersStratiotes aloidespriorityAnot listedAnot listed
Medusahead ryeTaeniatherum caput-medusaepriorityBnot listedCC
SaltcedarTamarix ramosissimaB,TBWB
Spurge flaxThymelaea passerinanot listedBnot listedW
European water chestnutTrapa natanspriorityAnot listedAA
PuncturevineTribulus terrestrispriorityBBCB
ColtsfootTussilago farfarapriorityABAA
Narrowleaf cattailTypha angustifolianot listedCnot listedC
Southern cattailTypha domingensisnot listedCnot listedW
Miniature cattailTypha minimanot listedCnot listedW
White cattailTypha x glaucanot listedCnot listedW
North Africa grassVentenata dubia ( V. avenacea )BCnot listedC
Japanese eelgrassZostera japonicaWCnot listedW
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