Japanese KnotweedJapanese Knotweed

By Linda TuckerBy Linda Tucker

Polygonum cupsidatumPolygonum cupsidatum

Also called Also called Fallopia joponicaFallopia joponica Buckwheat family (Buckwheat family (PolygonaceaePolygonaceae)) Common names:Common names:

Japanese KnotweedJapanese Knotweed Mexican BambooMexican Bamboo Chinese ChokeweedChinese Chokeweed

Native to eastern AsiaNative to eastern Asia

How Did it Get Here?How Did it Get Here?

First introduced from Japan into the First introduced from Japan into the United Kingdom in 1825United Kingdom in 1825

Was introduced to the United States from Was introduced to the United States from the U.K. in the late 1800sthe U.K. in the late 1800s

Introduced as an ornamental plantIntroduced as an ornamental plant In recent history, heavily planted at mine In recent history, heavily planted at mine

reclamation sites in PAreclamation sites in PA

About the PlantAbout the Plant

PerennialPerennial Grows between 3 and 10 feet highGrows between 3 and 10 feet high Stems are reddish green, jointed, and Stems are reddish green, jointed, and

hollowhollow Broad, alternate leavesBroad, alternate leaves Flowers: small and greenish white and Flowers: small and greenish white and

grow in spikesgrow in spikes

What Does It Look Like?What Does It Look Like?

Where is it Found?Where is it Found?

Moist environments, such as stream Moist environments, such as stream banks, islands, and wetlandsbanks, islands, and wetlands

Also found along roadsides and railroadsAlso found along roadsides and railroads Can live in open sun or partial shadeCan live in open sun or partial shade Can tolerate harsh conditions such as Can tolerate harsh conditions such as

high temperatures, high salinity, high temperatures, high salinity, droughts, and floodsdroughts, and floods

DistributionDistribution

How Does it Spread?How Does it Spread?

Reproduces through Reproduces through two methods:two methods: SeedsSeeds Fragmentation of the Fragmentation of the

rhizomerhizome

Rhizome can be 40 Rhizome can be 40 to 60 feet in lengthto 60 feet in length

Ecological ImpactsEcological Impacts

Japanese knotweed grows quickly and Japanese knotweed grows quickly and denselydensely

Crowds out native plants and limits Crowds out native plants and limits biodiversitybiodiversity

Causes stream banks to be less stable Causes stream banks to be less stable and susceptible to erosion during floodsand susceptible to erosion during floods

Urban ImpactsUrban Impacts

How to Get Rid of ItHow to Get Rid of It

Eradication is very difficultEradication is very difficult If it is cut, it will grow back due to the rhizomeIf it is cut, it will grow back due to the rhizome It can be dug up, but any remaining rhizome It can be dug up, but any remaining rhizome

can grow back and you can actually spread the can grow back and you can actually spread the rhizome this wayrhizome this way

Herbicides such as Glyphosate and Triclopyr Herbicides such as Glyphosate and Triclopyr can be used effectively in combination with can be used effectively in combination with cuttingcutting

How to Prevent How to Prevent SpreadingSpreading

Don’t plant Japanese KnotweedDon’t plant Japanese Knotweed Wash your shoes before entering and Wash your shoes before entering and

after leaving natural areas to remove after leaving natural areas to remove seedsseeds

Do not dig up the rhizome, as you may Do not dig up the rhizome, as you may accidentally spread rhizome fragmentsaccidentally spread rhizome fragments

Some Positive QualitiesSome Positive Qualities

Excellent source of vitamins A and CExcellent source of vitamins A and C Good source of resveratrol, which can Good source of resveratrol, which can

lower bad cholesterol and reduce the risk lower bad cholesterol and reduce the risk of heart attackof heart attack

Tastes similar to rhubarb and can be Tastes similar to rhubarb and can be used in baked goods, soups, used in baked goods, soups, marmalades, or just steamed and eatenmarmalades, or just steamed and eaten

ReferencesReferences

http://www.in.gov/dnr/files/Japanese_Knotweedhttp://www.in.gov/dnr/files/Japanese_Knotweed.pdf.pdf

http://dnr.wi.gov/invasives/publications/pdfs/http://dnr.wi.gov/invasives/publications/pdfs/japanese_knotweed_control.pdfjapanese_knotweed_control.pdf

http://www.forestpests.org/acrobat/jknot.pdfhttp://www.forestpests.org/acrobat/jknot.pdf http://www.wildmanstevebrill.com/http://www.wildmanstevebrill.com/

Plants.Folder/Knotweed.htmlPlants.Folder/Knotweed.html http://www.dcnr.state.pa.us/forestry/http://www.dcnr.state.pa.us/forestry/

invasivetutorial/japanese_knotweed.htminvasivetutorial/japanese_knotweed.htm

Questions or Comments?Questions or Comments?