1. Cityof-l
VeferonsMemoriql Pqrk
ConfrolMethodsond Moinlenonce of
JoponeseKnolweed,Polygonumcvspidatum
It iswifh recommendotionos o supplementto the Invosive ControlPlon
provided to the Cify prepored by by ceriified soil
scienlisf Stonley Il, odditionol control methods ond mointenonce is
considered to eliminote ond potentiolly erodicote delineated potches of
JoponeseKnotweed,Polygonurncuspidotumfound on Site.
PHASEI point no. 8 of the InvosivePlontMonogemenl Ploncollsfor excovotion
of the noxiousond invosiveplont species,segregoteexcovoted soilwithresiduol
plont portsremovedto o non sensitivelocotionoffsite.Thespecifiedcontroctor,
tConstruction,isondwosrequiredtoremoveol|plontmoteriolondsoil
underlyingthe plontslo o minimumdepth of 36 inches. All contominqted fill
moteriolfromthe specifiedoreo isnot to be reusedof the siie.
Should contominoted fill moferiol be reused on site il is recommended to
considerthe moteriol 'octivelyinvosive'given thof stem or root frogmentscon
olso be spreod in contominoted fill moteriol. Jcponese Knotweed hos on
exfensiverhizomesystempotentiollyspreodingbeh,rreen23' - 65' owoy from the
porent plont ond potentiollypenetrotingof leqst7' inlo the soil. Knotweedcon
ropidly reproduce vegetotivelyfrom root ond slem frogmentsos smol]es 1/2"
formingnew plont colonies. Brokenond/or cut sfemsond rootswillsproufif left
in moistsoilor directlyploced inwoler.
Giventhot Knolweediso creeping perenniolit hqso specifiedgrowingseqson,
April - August, ond dies bock to the ground with the firsf hord frosi. lt is
recommended thof o NoxiousWeed Monogement ControlPlonbe estoblished
by the Cityfor ollinvosiveplont speciesdelineotedon the Sife.
REMEDIATIONTECHNIQUESANDAPPL]CATIONS
o Reuseof octivelyinvosivefillmoleriqlshouldbe buriedo minimumdepth
of l0'ond of leost 20'feet owoy from the originolpotch center. To
preventnew growthit isrecommended lhe contominoted fillmqleriolbe
covered with q filterfobric extended of leost6' beyond the perimeterof
the fill moteriol. Frequentcutfing ond/or mowing is requiredto control
resprouting.

2. . Betweenthe specifiedgrowingseosons,April- August,cutting ond
mointenonceshouldoccurof leosttwiceo monthto confrolresprouting.
lf isrecommendedthol hondcuttingshouldbe done of leostevery2-3
during the growing seoson. Sprouting slows ofler August ond
mointenoncecon be scoledbockof fhottime.
o Remove,roke ond dry oll Knotweed thot is cul or mowed to prevent
reesfoblishment.
o When cutting ond mowing, cut qs low os possibleond specified os
obove.
Diggingond pullingmojorrhizomessystemsby the root crown willreduce
the roof mqss.
Herbicide opplicotion meihods include sproying, wicking, injecting,
pouringor combinolionsof.
Herbicidesmusl be opplied by o licensed opplicqtor; consultctionof
product use cqn be locoted of the Deportmenf of Agriculture.locol
exfensionogenl, pesticidedeoler,or herbicidemonufocturer.
Consultthe lobelon herbicidesforopplicotionmethodsincluding:
o Correctconcenlrotionroles
o Therighfopplicotionmethod
o Thecorrectfimingto coincidewith plont susceptibilbily
o An odjuvontif recommended
. Adjuvonfs ore sproy solutionodditives thot moy moke herbicides more
effective they move the chemicol from the leovesinto the roof systems
(i.e.beingtronslocqfed).
SOURCES
. Soll,Jonothqn.0l.l 6.04ControllingKnotweedin the Pacific
Norfhwesf.TheNotureConservoncyof Oregon.
ADDITIONALRESOURCES
. Child,Loisond Mox Wode.2000TheJapaneseknofweedmanuol-
the monagemenf ond controlof on invosiyeolienureed. Pockord
PublistiingLimited