Would you like to find out more about us, or about …weeds, but if they do, they become very...

GEHO0410BSBR-E-E

Environmentfirst:Thispublicationisprintedonpapermade from100percentpreviouslyusedwaste.By-productsfrommakingthepulpandpaperareusedforcompostingandfertiliser,formakingcementandforgeneratingenergy.

* Approximate call costs: 8p plus 6p per minute (standard landline).Please note charges will vary across telephone providers.

Would you like to find out more about us, or about your environment?

Then call us on 08708 506 506* (Mon-Fri8-6)

email [email protected]

or visit our website www.environment-agency.gov.uk

incident hotline 0800 80 70 60 (24hrs)

floodline 0845 988 1188

managing invasive non-native plants

Managinginvasivenon-nativeplantsinornearfreshwater

RevisedversionApril2010

Environment AgencyManaginginvasivenon-nativeplantsinornearfreshwater1

WearetheEnvironmentAgency.It’sourjobtolookafteryourenvironmentandmakeitabetterplace–foryou,andforfuturegenerations.

Yourenvironmentistheairyoubreathe,thewateryoudrinkandthegroundyouwalkon.Workingwithbusiness,Governmentandsocietyasawhole,wearemakingyourenvironmentcleanerandhealthier.

TheEnvironmentAgency.Outthere,makingyourenvironmentabetterplace.

Publishedby:

EnvironmentAgencyRioHouseWatersideDrive,AztecWestAlmondsbury,BristolBS324UDTel:08708506506Email:[email protected]

©EnvironmentAgency

Allrightsreserved.Thisdocumentmaybereproduced

withpriorpermissionoftheEnvironmentAgency.

April2010

Foreword

People living in and visiting England and Wales are able to enjoy and benefit from a wide range of native plant-life. But sometimes the natural diversity is threatened by the introduction and spread of invasive non-native species.

Whileonlyasmallpercentageofnon-nativeplantsintroducedinEnglandandWalesrepresentaproblem,whentheydobecomeestablishedinthewild,certaintypescanhaveadramaticeffect.Carelessdisposalofgardenwaste,bydumpingitoverfences,hedgesandintolay-bys,ditches,streamsandponds,increasesthechancesoftheseplantsspreadingintothecountryside.Thiscanleadtolong-termconsequencesfornativebiodiversity.

Invasivenon-nativespeciescanharmtheenvironmentindifferentways.WhilstHimalayanbalsamandwaterprimrosearecolourfulandattractive,theyoftenbecomesoprolificthattheydisplacenativeplants.Densematsoffloatingpennywortorparrot’sfeathercanchokewatercoursesleadingtoincreasedfloodrisk,reducedanglingopportunitiesandproblemsfornavigation.

Severalnon-nativespeciesarealreadywell-establishedandarelikelytospreadfurtherasaresultofclimatechange.Othersthatarecurrentlynotaproblemcouldbecomeinvasiveastemperaturerisescreatebettergrowingconditionsforthem.TheInvasiveNon-NativeSpeciesFrameworkStrategyforGreatBritainlaunchedinMay2008,byDefraandthedevolvedadministrations,hasspurredpublicandprivatesectororganisations,charities,localgroupsandindividualsintoactionandmuchgoodworkhasbeendonetotacklelocalproblems.Thepurposeofthisguidanceistoincreaseawarenessofsomeoftheinvasivenon-nativeplantsthatareapriorityforusandtoprovideadviceonhowtheproblemstheycausecanbereduced.

Wearepublishingthisrevisedguidance,intheInternationalYearofBiodiversity,aspartofourcontributiontotheconservationofwildlifealongthewaterwaysandfreshwatersinEnglandandWales.

Paul Leinster ChiefExecutive,EnvironmentAgency

2Environment AgencyManaginginvasivenon-nativeplantsinornearfreshwater Environment AgencyManaginginvasivenon-nativeplantsinornearfreshwater3

Contents Whatareinvasiveweeds?Severaltypesofplantcanbecomeinvasiveweeds.Theyareeithernativespeciesthatgrowwellindisturbedornutrient-enrichedconditions,tothedetrimentofotherplantandanimalspecies,ornon-nativeplantsthathavebeenintroducedtothiscountrybyaccidentorasaconsequenceoftradeordeliberatecollection.Thelattertendtogrowinsituationswherenativeplantsofsimilarformdonot.Notallnon-nativespeciesbecomeweeds,butiftheydo,theybecomeverydifficulttocontrol.Nativeweedspecies,althoughtroublesome,donotcauseasmuchecologicalorphysicaldamageasthenon-nativevariety.Thisbookletdealswiththosenon-nativeinvasivespeciesthathavecausedseriousproblemsintheaquaticandriparianenvironmentsofBritain.

Invasivenon-nativespeciestendtosharecharacteristicsthatmakethemsuccessful.Thesearerelatedtothemethodofreproduction,growthrate,growthformandpersistence,butinparticulartheabsenceofpestsanddiseasesandtheirconsequentresistancetocontrol.Speciesinaquaticplantfamiliesaremorelikelytobebothweedyandinvadersofnaturalenvironmentsthanthoseofanyotherplantfamilies.Inaddition,thefrequentlydisturbednature

ofman-madeaquatichabitatsandartificialnutrientenrichmentofaquaticsystemsmakesthemmorepronetoinvasion.Successfulmanagementofalieninvasivespeciesrequiresanunderstandingofhowtheygrowandalsotheecologyoftheaquaticsystemsinwhichtheyoccur.

Theintroductionofplantspeciesintonewenvironmentscarriesrisks.Thedangerofspeciesbecomingseriousweedsinagriculturalareasiswellcontrolled,butotherpotentialweedsarenotcurrentlyrecognisedandsubjecttoriskassessmentandmanagement.Theeffectsofclimatechangewillalterthedistributionofweedspeciesinfuture;already,severalaquaticweedsfoundinEuropeoriginatedinsub-tropicalareasoftheworld.Thepredictedconsequencesofglobalwarming,includingincreasedtemperatures,increasedcarbondioxideandstormierweather,makeitmorelikelythatadditionalinvasivespecieswillcauseproblemsinfuture.ThehugeincreaseinthedistributionofHimalayanbalsamsince1962indicatesthatconditionsareideallysuitedforthisspecies.Otherspeciesmayrespondsimilarlyinfutureifclimatechangefavourstheircolonisationandrapidgrowth.Plantsthatgrowinwaterandonriverbankscancausefloodingifnotmanagedcorrectly.Allthespeciesdescribedinthisbookletcreateseriousfloodrisks.

Whatareinvasiveweeds? 3

Existinglegislation 4

Responsibilityforinvasiveweedcontrol 5

Generalmethodsofcontrol 5

Healthandsafety 6

Disposalofnon-nativeweeds 6

Monitoring 7

Japaneseknotweedfactfile 8

Gianthogweedfactfile 11

Himalayanbalsamfactfile 14

Australianswampstonecropfactfile 17

Parrot’sfeatherfactfile 20

Floatingpennywortfactfile 22

Creepingwaterprimrosefactfile 25

Glossary 28

Furtherinformation 29


responsibilityofanystatutoryorganisation.TheEnvironmentAgencymayseektocontrolspecificinvasiveweedsonlandthatitownsorflooddefencestructuresthatitmaintains.

Controleffortsbyindividualscanhelpreducethespreadofinvasivenon-nativespeciesandaremostsuccessfulifcarriedoutasacatchmentwideco-ordinatedstrategywithcollaborationofallrelevantparties.Controloftenneedstoberepeatedyearafteryear.

General methods of controlTherearefourbasicmethodsofcontrollingweeds:mechanical,chemical,naturalandenvironmental.Mechanicalcontrolincludescultivation,hoeing,pulling,cutting,raking,dredgingorothermethodstouprootorcutweeds.Chemicalcontrolusesspecificherbicides.Naturalcontrolusespestsanddiseasesofthetargetweedtoweakenitandpreventitfrombecominganuisance.Environmentalcontrolworksbyalteringtheenvironmenttomakeitlesssuitableforweedgrowth,forexamplebyincreasingordecreasingwatervelocity.

In England and Wales the use of herbicides in or near rivers, canals, lakes and drainage channels requires prior agreement from the Environment Agency. Users must follow the instructions on the label.

TheNon-NativeSpeciesSecretariathasbeenestablishedtooverseetheimplementationofthestrategy.Detailsofthesecretariatareavailableatwww.nonnativespecies.org.Thissitealsoprovidesvaluablereferencematerial,suchasidentificationsheets,speciesriskassessmentsandactionplans,anddetailsoflocalactiongroupsthatmaybeactiveinyourarea.

ResponsibilityforinvasiveweedcontrolResponsibilityfordealingwithinvasiveweedsrestswithindividuallandowners.Strategic,widespreadcontroliscurrentlynotthesole

TheWildlifeandCountrysideAct1981providestheprimarycontrolsonthereleaseofnon-nativespeciesintothewildinGreatBritain.Itisanoffenceundersection14(2)oftheActto‘plantorotherwisecausetogrowinthewild’anyplantlistedinSchedule9,PartII.ThesevenplantsdescribedwithinthisbookletwillallbeincludedinSchedule9fromApril2010.

StricterenforcementprovisionsforwildlifeoffenceswereintroducedundertheCountrysideandRightsofWayAct2000.TheseincludeincreasedpenaltiesavailabletothecourtsforoffencescommittedundertheWildlifeandCountrysideAct1981.

TheWeedsAct1959providesforthecontroloffivespecifiedweeds.Thesearenonaquaticspecies,thoughragwort,(Senecio jacobaea),cangrowinriparianareas.Thislegislationisdirectedatclearingweedsthatthreatenagriculturalproduction.

TheGovernmenthasacknowledgedtheproblemsthatcanbecausedbynon-nativeinvasivespecies.In2008theGovernmentlaunched‘TheInvasiveNon-NativeSpeciesFrameworkStrategyforGreatBritain’.Thestrategyprovidesaframeworkforamoreco-ordinatedapproachtoinvasivespeciesmanagement.Itseekstocreateastrongersenseofsharedresponsibilityacrossgovernment,keyorganisations,landmanagersandthepublic.

Theconsequencesandcostsofinvasivenon-nativespeciesarehuge.Theannualcostofinvasivenon-nativespeciesinEuropeisestimatedasatleast19.1billionEurosayear.Thisbooklettellsyouhowtoidentifysevenproblemspeciesandhowtoreducetheirthreattoaquaticecosystems.

ExistinglegislationWhennon-nativespeciesbecomeinvasivetheycantransformecosystems,causingavarietyofproblemsincludingseriouslythreateningnativeandendangeredspecies.Theseproblemsareacknowledgedinseveralinternationaltreaties,EuropeanUnionDirectivesandalsoindomesticlegislation.Theproblemscausedbysomeinvasivenon-nativespeciesoccurworldwide,andinternationalobligationstoaddressthemareplacedontheUnitedKingdomthroughregionalandglobalagreements.TheseincludetheConventiononBiologicalDiversity(CBD),InternationalPlantProtectionConvention(IPPC),theBernConventionontheConservationofEuropeanWildlifeandNaturalHabitats,andtheECHabitatsandSpeciesDirective.ThesixthCBDconferenceadoptedaseriesofGuidingPrinciplesforStatestofollowaspartoftheirinvasivenon-nativespeciespolicies.

Other legislation relevant to non-native species control includes:

• EnvironmentalProtectionAct1990

• EnvironmentalProtection(DutyofCare)Regulations1991

• TownandCountryPlanningAct1990

• HighwaysAct1980

• WaterResourcesAct1991

• TheEnvironmentalPermitting(EnglandandWales)Regulations2007

• TheLandfill(EnglandandWales)Regulations2002


MonitoringNewrecordsoftheplantsdescribedinthisbookletwillbehelpfulinassessinghowfasttheyarespreadinganddetermininglocalcontroloptions.Ifyouseeanyofthesespecies,pleasetellDrJonathanNewman,CentreforEcologyandHydrology–[email protected],ortelephone01491 692556.Informationrequiredistheexactlocation,withamapgridreferenceifpossible,theextentoftheinfestationandthekindofwaterbodyitisaffecting.

Thecorrectdisposalofplantmaterialaspartofmechanicalcontrolisvital.ItisbesttocontacttheEnvironmentAgencyforadviceondisposalbecausethereareRegulationswhichcoverthecomposting,burningandburialofplantmaterialson-siteandtransferanddisposalofmaterialtopermittedlandfillsites.Anyburningmustnotproduceexcesssmokeorcreateanuisanceandmusttakeplaceonahotfireconsistingofwoodorcleantimber.Plasticandotherrubbishmustnotbeburnt.TyresandpetrolmustNEVERbeusedtostartafire.TheEnvironmentAgencycangiveadviceonsuitabledisposalsitesanddisposalmethods.

JapaneseknotweedwillsurvivecompostingandthereforethismethodofdisposalisNOTadvisable.JapaneseknotweedmustonlybeburiedorburntinaccordancewithEnvironmentAgencyadvice.Failuretoensuresafelegaldisposalorobtainanappropriatelicenceorexemptioncouldresultinprosecution.Burialon-sitemayrequirealicenceundertheLandfillRegulations2002,whilstremovalofplantmaterialwillneedtobecarriedoutbyalicensedwastecarrierandburiedatalicensedlandfillsite.Furtheradviceisavailablefrom‘Theknotweedcodeofpractice–managingJapaneseknotweedondevelopmentsites’,publishedbytheEnvironmentAgency.

Health and safetyTakecarewhenusingmachineryorherbicides.EnvironmentAgencystaff,contractorsandothersshouldundertakeControlofSubstancesHazardoustoHealth(COSHH)assessmentsfortheactivity,andothersshouldbeawareoftherisksofworkingnearwater.Thereisoftenahighriskofslippingonbanksandothermuddysurfaceswhencarryingequipmentorchemicals.

Allmixingandapplicationofherbicidesmustbecarriedoutinaccordancewiththemanufacturer’sinstructions,whichwillbefoundontheproductlabel.Allprecautionsrecommendedbythemanufacturermustbefollowed.

Althoughmostspeciesinthisbookletarenottoxictohumans,greatcareshouldbetakentoavoidcontactwiththesapofgianthogweed,asthiscancauseseriousskinblistering.

Disposal of non-native weedsPlantmaterialisconsidereda‘controlledwaste’andmustbedisposedofinaccordancewith,andenvironmentalpermitissuedunder,theEnvironmentalPermitting(EnglandandWales)Regulations2007,unlessoneoftheexemptionssetoutinSchedule3oftheseregulationsapplies,althoughexemptionsalsorequireregistrationwiththeEnvironmentAgency.

What to do and what not to do

Do:

• take immediate action;

• contacttheCentreforEcologyandHydrologytoconfirmidentificationandthelocationoftheplant;

• seekadviceoncorrectmanagementforyourspecificlocation;

• obtainapprovalfromtheEnvironmentAgencyifplanningtouseherbicides;

• removeallplantdebrisfromthewateraftercuttingoperations;

• seekadvicefromtheEnvironmentAgencyonthedisposalofplantmaterial;

• alertyourneighbourstotheproblem.

Don’t:

• delay in doing something;

• allowtheplanttospreadtonearbywaterbodies;

• disposeofcutmaterialinthenearestwaterbody;

• useinvasivenon-nativespeciesinhabitatrestorationprojects.


Chemicalcontrolusingabiactiveformulationofglyphosateapprovedforuseinornearwateristhemosteffectivetreatmentnearwater.Spraying both top and underside of leaves improves control.ChemicaltreatmentismosteffectivewhenitisappliedinAug-Sept,particularlywhenappliedtomatureuncutgrowth.Thisprovidesthegreatestsurfaceareaforherbicidetobetranslocateddowntotherhizome.Asteminjectionmethodcanbeusedtoavoiddamagetosurroundingsensitiveareas.

TheknotweedcodeofpracticeisavailableontheEnvironmentAgencywebsite.CopiescanalsoberequestedbycallingtheEnvironmentAgencyNationalCustomerCallCentreon08708506506.ThecodewaswrittentoprovideadviceonthemanagementofJapaneseknotweedondevelopmentsites,butmuchoftheadviceregardingcontrolanddisposalmaybeusefulforripariancontrol.

Theundergroundrhizomesystemcanextendatleast7mfromtheparentplant,andreachadepthof3mormore.Apieceofrhizomethesizeofalittlefingernailcangrowintoanewplant.Thecrown,locatedatthebaseofthestem,willproducenewplants.Thestemsdiebackinwinterandtakeuptothreeyearstodecompose.Japaneseknotweedshouldnotberemovedfromsitewithoutawastelicence.

ControlKnotweedshouldbecutwithasinglecleancutnearthebaseofthestem.Cuttingmethodsthatproducefragments,suchasflailing,shouldbeavoided.Stemscanregeneratefromnodes,orfragmentsofnodes.Ifcutstemisdrieduntilitiscrispandbrownitcanbeburntordisposedofasaninertwaste.If stems have been pulled up, they will have fragments of knotweed crown still attached at their base. This is highly regenerative and will regrow, even after the stem has dried. Avoid pulling stems. Refer to the code of practice for their disposal.

mostwidespreadandtroublesomebanksidespecies,followedcloselybyhybridknotweed,whichhasasimilarlyhighregenerationcapacity.

OnlyfemaleplantsarepresentintheUK.Japaneseknotweedformsdenseclumpswithfleshy,red/greenshoots,2-3mtall,whichhavehollowgreenstemswithred/purpleflecks.Leavesaregreen,heartorshield-shapedwithaflatbase,upto120mmlong.Creamyclustersofflowersareborneonthetipsofmoststemsinlatesummer.Therootsystemconsistsofrhizomeswhichareorange/yellowwhencut.

JapaneseknotweedwasfirstbroughttoBritaininthemid-nineteenthcenturyasanornamentalgardenplant.Sincethenithascausedseriousproblemsinarangeofhabitats–particularlyroadsides,riverbanksandderelictland–bydisplacingnativefloraandevencausingstructuraldamage.TherearethreespeciesofinvasiveknotweedintheUK:Japaneseknotweed(Fallopia japonica);giantknotweed(Fallopia sachalinensis);andhybridknotweed(Fallopia x bohemica),whichisacrossbetweenJapaneseandgiantknotweed.Japaneseknotweedisthe

Fact file

Japaneseknotweed

Source:NBNGateway.Checkwebsiteforcurrentdistribution


Chemical control

Glyphosate GlyphosateismoreeffectivewhenappliedtomaturecanesinAug-Sept.Ifaccessortheriskofdriftisaproblem,eithercutorspraythestemsearlierintheseasontorestrictregrowth.Forformulationsapprovedforstumptreatment,a1in10dilutioncanbeusedforsteminjection.

2,4-D amine 2,4-DAmineisalsoeffectiveagainstknotweedandisbestappliedinMay.

In general Herbicidescanbeappliedusingtractor-mounted,knapsacklong-lanceorCDAapplicators.Controliseasierifdeadwinterstemsareremovedbeforegrowthcommences.Becarefultoavoidspreadingknotweedcrownswhenclearingdeadcanes.Applicationinsensitiveareasisbestachievedbysteminjectionorweedwiper.

Non-chemical control

Cutting Useasimplescythemethodofcuttingtopreventstemfragmentation.Flailmowing,orsimilarmethods,shouldnotbeundertaken.

Cuttingwillhavetobeperformedevery2-4weeksduringthegrowingseasonifitisthesolemethodofmanagement.Alternatively,treatregrowthwithherbicide.

Burncutstemsonsiteorremovetolandfill(licencerequired).

Digging Thisisrarelyanoptionthatisappropriatetoripariansituations.Ifdiggingisundertaken,refertothecodeofpracticeandensurethatnoknotweedmaterialisallowedtoenterthewatercourse.

Biological Grazingofshootsbyhorses,donkeys,sheepandgoatsmaykeeptheplantincheck,providedpreviousdeadgrowthisremoved.

ThepsyllidbugAphalara itadoriwillbereleasedin2010andshouldreducethevigourofJapaneseknotweedintheUK.

andgrasses,leavingthebanksbareofvegetationinwinterandincreasingtheriskoferosionandrecolonisationfromseedswasheddownstream.

GrowthstartsinMarchandtheplantsreach5minheight.Theleavesaredarkgreen,andformarosette.Thelobesaredeeplycutandspikedattheends.Thestemsaregreenwithdarkredorpurplespotsorblotches.Stemsareribbed,withsparsespikyhairsontheridges.Thestemsarehollowandupto100mmacross.Theflowersarewhite,formingalargeumbel.Eachplantproducesupto50,000seeds,

Gianthogweed(Heracleum mantegazzianum),isanativeoftheCaucasusmountainsandwasintroducedtoBritainin1893asanornamentalplant.Itescapedfromgardensandnowcolonisesmanyareasofwastelandandriverbanks.Eachflowerheadproducesseveralthousandseedsthatareeasilydispersedbywater,sotheplantspreadsrapidlyalongwatercourses.

Itisaperennialplant,takinguptofouryearstomatureandflower,afterwhichitdies.Itformsdensecoloniesthatsuppressthegrowthofnativeplants

Fact file

Gianthogweed


Contact the Environment Agency for disposal advice on 08708 506 506


Health hazardChildrenhavebeenknowntousethehollowstemsas‘peashooters’and‘telescopes’.However,thestems,edgesandundersidesoftheleavesbearsmallhairscontainingpoisonoussap,andtheslightesttouchcausespainfulblisteringandsevereskinirritation.Unshadedhabitatswithhighsoilnitratelevels(forexample,riverbanks,roadsidesandwasteground)tendtoproducegreaterquantitiesoftoxinsintheplant.Contactwiththecutmaterialinsunlightproducesaskinreactioninalmostallcases.Blisteringsymptomsoccur24-48hoursafterexposure,anddensepigmentationisvisibleafterthreetofivedays.Thismaypersistforsixyearsormore.Cutmaterialremainsactiveforseveralhoursaftercutting.Protectiveclothingmustbewornwhentreatingthisplantbecausethehairscanpenetratelightfabrics.

approximately10mmlongby7mmwide.Seedsmayremainviableforupto15years.

ControlTheaimshouldbetokilltheplantorpreventflowering.Repeatedtreatmentmaybenecessaryduringthegrowingseasontopreventflowering.

Chemicalcontrolusingglyphosateat6litres/haisthemosteffectivemethod.Sprayingcanstartassoonastheplantisabout1mhigh,usuallyinMarchandcontinuethroughoutthesummer.Morethanoneapplicationisoftennecessaryandfollow-upsprayingwillberequiredtokillseedlingsinsubsequentyears.

Cuttingdownthestemswithasharpscytheorsicklebeforefloweringwillhelptocontrolthisplant.Flailmowingmaybecarriedout,butextremecautionisrequiredtoavoidtheriskofbeingsprayedwithsap.Strimmingisnotrecommended,unlessfullprotectiveclothingisworn.

Diggingoutthecrownjustbelowgroundpreventsregrowthandwillprovidegoodcontrol.Alternatively,makeaspadecutat45degreestoseverthetaprootatapproximately15cmbelowsoillevel.


Chemical control

Glyphosate Inmixedstands,useaweedwipewhenplantsareabout1mtallbetweenMarchandMay.Whenplantsaremorethan1.5mtall,proceedwithextremecaution.Repeatchemicaltreatmentmayberequiredforupto10years.

Cuttingthestemaboveground,followedbyinjectionof1in10dilutionofglyphosateinwaterbelowthefirstnode,willgivegoodcontrol.Thistechniquecanbeusedforestablishedplantslaterintheseason.

In general Itisessentialtoestablishvegetationquicklyaftercontrolmeasureshavebeenapplied.Densegrassswardtendstodiscourageseedgermination.Controlshouldbeundertakenonacatchmentbasis,workingfromtheupstreamendtopreventseedrecolonisation.


Cutting Cutrootapproximately15cmbelowgroundusingaspade.Wearfullprotectiveclothing,especiallyifstrimming.Cutregularlyearlyintheseasontopreventflowering.Cuttingshouldberepeatedregularlyforbetween5and10yearstoeradicatetheplant.

Digging Shallowexcavationtoabout20cmwillremovethegrowingcrown.Spoilshouldbedisposedofatlandfillorbypilingonsiteandcomposting.Anyregrowthshouldbetreatedchemically.

Biological Grazingbycattle,sheep,pigsorgoatsthroughoutthegrowingseasonwillsuppressgrowth,butdoesnoteradicateit.Thereisfurtherresearchintopotentialbiologicalcontrols.


Himalayanbalsamplantsgrowindensestandsthatsuppressthegrowthofnativegrassesandotherflora.Inautumntheplantsdieback,leavingthebanksbareofvegetation,andthereforeliabletoerosion.

Thestemsarepinkish-red,hollowandjointed,oftenwithsomebranching.Leavesandsidebranchesoriginatefromstemjoints.Thestemissappyandbrittle.Theshinydarkgreenleavesarelance-shaped,haveserratededges,adarkredmidrib

HimalayanorIndianbalsam(Impatiens glandulifera)isanativeofthewesternHimalayas.IntroducedtoBritainin1839,itescapedfromgardensandrapidlycolonisedriverbanksandareasofdampground.ItisthetallestannualplantinBritain,growingupto3mhigh.Thecharacteristicpurplish-pinkslipper-shapedflowersappearinJune.Whentheseedpodsmature,theyexplodewhentouched,scatteringtheseedupto7maway.Seedsarealsospreadbywaterandtheymayremainviableforuptotwoyears.

Fact file

Himalayanbalsam


andcanbeupto150mmlong.Theygrowonthesteminwhorlsofthree.Purplish-pinkflowers,heldonlongstalks,appearfromJunetoOctober.

Thewhite,brownorblackseedsareproducedfromJulytoOctoberandare4-7mmindiameter.Therearebetween4and16seedsperpod.

ControlControlmeasuresshouldaimtopreventflowering,andarebestcarriedoutbeforeJuneformaximumeffectiveness.

Chemicalcontrolnearwatercanbecarriedoutwithherbicidescontainingglyphosateor2,4-Damine.Glyphosatewillalsokillgrasses,but2,4-Daminewillkillonlybroad-leavedweeds;forbesteffect,usewhentheplantissmallandactivelygrowing,particularlyinspringtime.

Cutting,strimmingorpullingonaregularbasisforaboutthreeyearswillbeeffectiveandmayeveneradicatetheplantfromisolatedsites.Plantsmustbecutbelowthelowestnodetoavoidreflowering.




Cutting Cutatgroundlevelusingascythe,machete,flailorstrimmerbeforethefloweringstageinJune.Cuttingearlierthanthiswillpromotegreaterseedproductionfromplantsthatregrow.Cuttingshouldberepeatedannuallyuntilnomoregrowthoccurs.

Pulling Shallow-rootedplantscanbepulledupveryeasilyanddisposedofbyburning,orcompostingunlessseedsarepresent.

Biological GrazingbycattleandsheepiseffectivefromAprilthroughoutthegrowingseason.Itshouldbecontinueduntilnonewgrowthoccurs.Thereisencouragingevidenceforthepotentialforbiologicalcontrol.

Chemical control

Glyphosate Treatmentwithaweedwipeinmixedstands,orbyfoliarsprayindensestands,beforeflowering.Ifallplantsarecontrolled,thensprayingprogrammesshouldonlyberequiredfortwotothreeyears.

2,4-D amineTreatduringearlyspringattherosettestageforeffectivecontrol.

In generalItisessentialtoestablishvegetationquicklyaftercontrolmeasureshavebeenapplied.Densegrassswardtendstodiscourageseedgermination.Controlshouldbeundertakenonacatchmentbasis,workingfromtheupstreamendtopreventseedrecolonisation.

Theplantiseasilydispersedand,althoughnotalwayssoldbysuppliers,itisoftenfoundasa‘contaminant’withotherwaterplants.Introductionstonewsitesareassociatedwithawiderangeofhuman,water-basedactivities,andawarenessandeducationprogrammescandramaticallyreducetransportoftheplantbetweensites.Localdispersalisaidedbythehighviabilityofsmallfragments,whichcanbecarriedonmudtonewsites.

ThesuccessofCrassulaliesmainlyinitsabilitytocolonisevirtuallyany

Australianswampstonecrop(Crassula helmsii)wasintroducedfromTasmaniatoBritainin1911.Itwasfirstsoldasan‘oxygenatingplant’in1927.

ThefirstoccurrenceinthewildwasreportedinEssexin1956.Inrecentyears,ithasspreadmuchmorerapidlyduetotheincreasedavailabilityoftheplantatgardencentresandaquaticnurseries.ItisnowwidespreadacrosstheUK.ItissometimesreferredtoasTillaea recurva,Tillaea helmsii,orNewZealandpigmyweed.

Fact file

Australianswampstonecrop



ControlThisplantisbesttreatedattheearlystagesofinfestation.Delaywillmaketheproblemseveralordersofmagnitudeworseineachsuccessiveyear.

Emergentgrowthcanbecontrolledusingahighlydilute,highvolumesolutionofglyphosate(5ml/l),appliedatawalkingrateof6secondspermetre.Thisprovidesatreatmentof6l/ha.

Cuttingisnotrecommended,butdredgingoutmarginalandemergentmaterialcanbeeffective,astheplantisshallow-rooted.Theareaaroundanyinfestationshouldbefencedtopreventmovementoffragmentsbylivestock.Dredgedmaterialshouldbepiledinheapsandcoveredwiththickblackpolythenesheetingoratleast20cmofsoil.

Shadingofterrestrialoremergentformswithopaquematerialsuchasblackpolytheneforaboutthreemonthsmaybeeffective,butisdifficulttoinstallandmanage,andvandalismcanbeaproblem.

suitablestatictovery-slow-flowingfreshwaterhabitatacrossawiderangeofwaterchemistry.Ithasvigorous,year-roundgrowth,andcangrowequallywelleitherondampgroundorinwaterupto3mdeep.

WhereCrassulainvades,itquicklyout-competesnativevegetation,andmaintainsitsdominancebyveryrapidgrowthanduptakeofalmostalltheavailablenutrients.

Therearethreetypicalgrowthforms:(i)aterrestrialformwithcreepingstemsandaerial,succulentleaves;(ii)anemergentformwithdenselypackedstems,foundinwaterlessthan0.6mdeep;(iii)andasubmergedformthatgrowsfromabasalrosettewithlong,sparsely-leavedstemsreachingthesurface.Thethreeformschangeaccordingtoprevailingconditions.Therigidstemshavepairsoffleshyleavesthatvaryinshapefromlongandnarrowindeeperwatertoslightlyelliptical,withsharporbluntishtipsinair.Theleaftipisnevernotched,whichdistinguishesitfromthenativewaterstarwort(Callitrichespp.).Theleafbasesarejoined,formingadistinctive1mmcollararoundthestem.Insummer,whiteflowersgrowintheaxilsoftheleavesonemergentandterrestrialforms.


Cutting Notrecommended.

Dredging Dredgingofmarginalandemergentmaterialthroughouttheyearcanbeeffective,althoughitisnecessarytoensurethatplantfragmentscannotbetransportedelsewhere.

Shading Coveringwithblackpolytheneorsimilarforupto3monthsduringthegrowingseason.


Chemical control

Glyphosate Applicationofglyphosateat6litres/hatoemergentstandsfromMarchtoOctober.Regulartreatmentisrequired,andatleasttwoapplicationsmaybenecessaryeachyear.

Submerged ThereisnoeffectiveherbicidetreatmentforsubmergedCrassula.Drawdownordrainthewaterbody,ifpossible,andtreatasemergentgrowth.

In general Regulartreatmentisnecessary.Weedwipingmaybeappropriateinmixedmarginalvegetation.Spottreatmentofsmallpatcheswillpreventcompletedominance.Treatearlyandregularly.


OnlyfemaleplantsareestablishedintheUKanditthereforespreadsbyvegetativemeansonly.Thestemsarebrittleandtheplantpropagatesbygrowthfromsmallstemfragments.Thespeciesisattractivetolookatandiswidelygrowningardenponds.Introductionstothewildareusuallynotdeliberate,butfragmentscanbeconcealedinthesoilofotherpotplantssoldataquaticgardencentresandnurseries.

Parrot’sfeather(Myriophyllum aquaticum)isanativeoflowlandcentralSouthAmerica.ItwasfirstfoundinBritainin1960andhasnowspreadextensively,particularlyinsouthernEngland.Itgrowsinponds,reservoirs,gravelpits,streams,canalsandditches,particularlywhereeutrophicwateroccurs.Itcangrowasaterrestrialplantwhenaponddriesout,andhasevenbeenfoundgrowingonthedrybankofarubbishtipinCornwall.Itproducesemergentshootsinadditiontosubmergedones,whichgiveitthecharacteristicfeatheryappearance,henceitsname.

Fact file

Parrot’sfeather


Volunteergroupscantacklelargeinfestationswiththeuseofrakesandforks.Careisneededtoensurefragmentsdonotdriftandestablishgrowthelsewhere.

ControlChemicalcontrolcanbeachievedbyapplyingglyphosatewiththeadjuvantTopfilmtoemergentgrowth.Hand-pullingcanbeaveryeffectivemethodofcontrol.


Pulling Materialmustberemovedfromthewaterassoonaspossible.Fragmentationmustbeavoided.MaterialshouldberemovedasoftenasnecessaryandatleasteverysixtonineweeksfromMarchtoOctobertoweakentheplant.

Dredging Dredgingshallowareaswillremovethisplantveryeffectively.Carefullypullingoutstemsbyhandaftermechanicalremovalwillhelptoeradicateit.

Biological Theplantisnotpalatabletoherbivores;cattleandhorseswillavoidit.ThereisvirtuallynoinsectdamagetoplantsintheUK,butresearchintobiologicalcontrolagentsisunderway.


Chemical control

Emergent Applyglyphosateat6litres/hatoemergentstandsfromMarchtoOctober.Regularannualtreatmentisrequired,andatleasttwoapplicationswillbenecessaryeachyear.TheadjuvantTopfilmimprovesefficacy.

In general Regulartreatmentisnecessary.Weedwipingwithglyphosatemaybeappropriateinmixedmarginalvegetation.Spottreatmentofsmallpatcheswillpreventcompletedominance.Treatearlyandregularly.


withboththeecologyandamenityusesofthewaterbody.Thesematsgrowupto15mfromthebankinasingleseason,withstemgrowthratesofupto20cmperday.

Floatingpennywortrootsfreelyfromnodesatapproximately40-150mmintervals.Therootsareprofuseandhair-like.Theleavesareemergent,risingonstalksfromhorizontallygrowingstems.Boththestemandthepetiolesarefleshy.Theleafformrangesfromcirculartokidney-shaped;theyaredeeplylobed,and

Floatingpennywort(Hydrocotyle ranunculoides)isanativeofNorthandSouthAmerica.ItwasfirstbroughttoBritaininthe1980sasaplantfortropicalaquariaandgardenponds,andwasfirstnotedinthewildinEssexin1991.

Floatingpennywortgrowsintheshallowmarginsofslow-flowingeutrophicwaterbodies(particularlyditches,slowflowingdykesandlakes),andformsdenseinterwovenmatsofvegetation.Thesequicklycoverthewatersurfaceinterfering

Fact file

Floatingpennywort


Control Chemicalcontrolcanbeachievedwithherbicidescontainingglyphosate.UseoftheadjuvantsTopFilmandCodacideOilimprovetheefficacyofglyphosate.

Cuttingandremovalisaverygoodmethodofmanagement,butitwillnotcontrolorreducethevigouroftheplant.Thecutordredgedmaterialshouldbeleftonsiteatthetopofthebank,wellawayfromwater.Manualremovalbyvolunteergroupshasprovedasuccessfulmethodofmanagement,particularlyforsmallersites.

upto180mmacross.Leavesareheldabovethewatersurfacewhilsttheinterwovenmatofrootsandstemssinkupto1.2mintothewater.

ReproductioninBritainisthoughttobeprincipallyvegetative,andtheplantiscapableofformingextensivematsfromthesmallestshootfragment.Introductionbyseedfromgrowthinindooraquaria,however,mayalsohaveoccurred.Floatingpennywortcandoubleitswetweightinaslittleasthreedays.TheplantexhibitsseasonallyvariablegrowthinBritain.Maximumgrowthoccursinthelatesummerwhenittypicallyformstheextensivefloatingmatsofvegetation,whilstitover-wintersinthemarginsandonbanksasamuchflatterandsmallerplant.

Theplantisrelativelyrestrictedinitsdistribution,largelyinsouthernEnglandandsouthWales.Itsappearanceislikelytohavebeenasaresultofescapesfromaquariaandgardenponds.Floatingpennyworthasalreadyprovedtobedifficulttocontrolbecauseofitsrapidgrowthrates,itsabilitytore-growfromasinglenode,anditsresistancetochemicalcontrol.



Cutting RegularcuttingfromMaytoOctoberwillpreventcompletedominanceofthisspecies.Cutmaterialshouldberemovedfromthewaterimmediately.Cuttingshouldbefollowedbyhandpullingorbyspottreatmentwithchemicalstoreducetheriskofregrowth.

Pulling or dredging Handpullingworksverywellinsmallinfestationsandasafollow-upaftermajormechanicalremoval.Eradicationispossibleusingthistechnique.

Biological Cattlegrazinghasbeenseentodamagetheemergentstems,butithasnolong-termeffectonthedominanceoftheplant.TherearenoknownbiologicalcontrolagentsintheUK,butresearchisunderway.


Chemical control

Glyphosate Applyingglyphosateat6litresproduct/hain400litresofwateristhemosteffectivetreatmentwiththischemicalparticularlywhenusedwithCodacideOil.Repeattreatmentswillbenecessarythroughoutthegrowingseasonassoonasregrowthoccurs.

In general Theplantdoesnotrotdownveryquicklyafterchemicaltreatment,andtreatedvegetationinflood-riskareasshouldberemovedaftertwotothreeweeksifpossible.Follow-upspottreatmentaftermechanicalremovalisrecommended.Regulartreatmentisnecessary.

roundorovalleavesthatcanbemistakenfornativebrooklime.Thestemsalsoextendacrossmud,intermittentlyrootingatnodes.Astheymature,thefleshystemsgrowuprightandtheleaveslengthenandbecomelanceolate,approximately9cmlong.Thefloweringstemscanbecomequitetallandresemblewillow-herb.

Creepingwaterprimrosethrivesinponds,lakes,watercourses,wetlandsandwetmeadows.Ithascurrentlybeenrecordedfromthirteensitesinthewild.Allof

CreepingwaterprimrosehasrecentlybeensoldintheUKasapondandaquariumplant.Itistradedunderavarietyofnames,includingprimrosewillowandJussiaea.ItscorrecttaxonomicattributionisequallyconfusedandLudwigia grandiflora,L. hexapetalaandL. peploides areamongthenamesthathavebeenappliedtoit.

Creepingwaterprimroseproducesadistinctiveyellowflower,approximately3cmacross,inJuly–September.Thestemsextendacrossthewatersurface,producing

Fact file

Creepingwaterprimrose

Image:AlainDutartreSource:NBNGateway.Checkwebsiteforcurrentdistribution


ControlChemicalcontrolcanbeachievedwithformulationsofglyphosateapprovedforuseinornearwater.Efficacyisgreatlyincreasedifitismixedwithanappropriateadjuvant,suchasTopfilmat1L/ha.

Carefulmanualremovalcanbeahighlyeffectivemethodofmanagement.ThisisthepreferredmethodofmanagementinFrancewhereherbicidetreatmentisnotallowed.IfLudwigiaiswellestablished,mechanicalremovalmaybeinitiallyusedtoreducethebiomass.Dredgedorpulledmaterialshouldbecompostedatsitesawayfromwaterbodiesorwetlandareas.

Manual,mechanicalorherbicidetreatmentislikelytorequireatleasttwoyearsofcontrol.Thesitewillneedtobesurveyedforanyresidualgrowthforatleastayearafterthelastgrowthhasbeentreated.Careshouldbetakennottospreadtheplantbyfragmentationusingthesemethods.

theseinfestationsareeitherbeingmanaged,orarebelievedtohavebeeneradicated.Whilstithasonlycausedminimaldamagetoourhabitatssofar,weknowfromthesituationinFrance,HollandandBelgiumthatthisplanthasthepotentialtocauseseriousdamagetoouraquaticenvironment.AneconomicstudyestimatedthatLudwigiacouldcosttheUKover£150millionperannumifitwereallowedtoestablish.

Whilstitisunlikelythatyouwillfindcreepingwaterprimroseinthewild,itisveryimportantthatanysitesatwhichitisfoundarereportedpromptlysothatcontrolcanbeundertaken.Thisplantisknowntobewidespreadinornamentalgardens,andthereforelikelytooccasionallyappearinthewildifitescapesfrompondsorisdisposedofinappropriately.


Pulling Hand-pullingworkswell,particularlywithsmallinfestationsandasafollow-uptochemicalormechanicalcontrol.Materialmustbecompostedawayfromwaterbodies.

Dredging Mechanicalremovaliseffective.Fragmentsmustbecontainedandremovedtoavoidfurtherspread.Materialmustbecompostedawayfromwaterbodies.

Chemical control

Glyphosate Applyglyphosateat6litresproduct/ha.AdditionoftheadjuvantTopfilmat1l/hagreatlyincreasesthestickinganduptakeofglyphosatethroughthewaxyleaves

Repeattreatmentsarenecessary,andregularmonitoringofthesiteisrequiredforbetweentwoandthreeyears.



FurtherinformationTherearemanysourcesofinformationaboutinvasiveplantsandmethodsofcontrollingthem.TheCentreforEcologyandHydrology(CEH)providesadviceonthecontrolofaquaticandriparianinvasivespecies.

ThispublicationgivesinvaluableinformationonmanagingJapaneseknotweed:

Environment Agency (2006)The knotweed code of practice – Managing Japanese knotweed on development sites.

Thefollowingwebsitesareveryusefulsourcesofinformationfornon-nativeinvasivespeciesingeneral:

GBnon-nativespeciessecretariat:www.nonnativespecies.org

CentreforEcologyandHydrology:www.ceh.ac.uk/sci_programmes/AquaticPlantManagement.html

CABI:www.cabi.org

TheGlobalInvasiveSpeciesProgramme:www.gisp.org

NationalBiodiversityNetwork(NBN):www.nbn.org.uk

TheWorldConservationUnion:www.iucn.org

Plantlife:www.plantlife.org.uk

ChemicalsRegulationDirectorate:www.pesticides.gov.uk

2,4-D amine–aselectivetranslocatedherbicide.

Adjuvant–aherbicideadditiveusedtoincreaseabsorptionoftheherbicidethroughthewaxyleavesofaquaticplants.

Axil–theanglewheretheleafjoinsthestem.

Biomass–theamountofplantmaterialproducedduringgrowth.

Contact–aherbicidethatkillsthepartsofplantstowhichitisapplied,forexampleleaves.

COSHH–ControlofSubstancesHazardoustoHealth.

Eutrophic–waterthathasanexcessofplantnutrients.

Glyphosate–anon-selective,translocatedherbicide.

Hybrid–offspringofcloselyrelatedspeciesthatareoftenmorevigorousthaneitheroftheparents.

Node–regionofattachmentofleavestothestemandofswellingonrhizomesfromwhichrootsandshootsarise.

Petiole–thestalkofaleaf.

Riparian–theareaattheedgeofwatercourses.

Selective–termusedforaherbicidethatkillsonlyonetypeofplant,forexampleonlygrassesoronlybroad-leavedweeds.

Succulent–fleshyorswollen.

Translocated–absorbedanddistributedthroughouttheplanttotherootsandshoots.

Whorl–acircularsetofleavesarisingatthesamelevelonastem.

Glossary

The‘BePlantWise’campaignprovidesadvicetogardenersoninvasivepondplantrecognition,guidanceonhowtodisposeofpondplantsandinformationontheimpactstheymayhaveintheenvironment.Postersandaleafletareavailablefromhttp://beplantwise.direct.gov.uk/index.html

Would you like to find out more about us, or about …weeds, but if they do, they become very...

Documents

Transcript of Would you like to find out more about us, or about …weeds, but if they do, they become very...