Invasive SpeciesJapanese knotweed

Fallopia japonica
FOUND by ahanson
Portland, ME
ID Confirmed
Quality checked by Simon Pritchard
Peer reviewed by
Field Notes
I was enjoying a summer evening walk in Baxter woods. The sun was setting as I walked but it remained warm (around 75 degrees fahrenheit). Because it was a warm summer evening the trail was filled with the sounds of dogs and people playing. Even though Baxter Woods is in the middle of Portland I could only hear cars when the trail was close to the road. The cars didn't drown out the occasional bird song! I was interested in seeing whether Baxter Woods had Japanese barberry and Japanese knotweed. I did some research prior to my walk and learned that Baxter Woods is a primary forest. However, I also learned through my research that Japanese barberry is common in secondary forests and therefore, was not expecting to find it in Baxter Woods. Nevertheless, I wanted to look for its presence because my research informed me that the Japanese barberry is an invasive species of particular concern because of the correlation scientists have found between the the presence of Japanese barberry and ticks. I was expecting to find Japanese knotweed, despite efforts by the Portland trails Association to remove it, because of its strong root system and ability to persist in an ecosystem. There was a little poison ivy right on the side of the trail that I narrowly avoided! As predicted, I did not find any Japanese barberry and did find Japanese knotweed. Interestingly I only found Japanese knotweed in one small cluster not throughout the forest.
Supporting Evidence
Photo of my evidence.
Japanese knotweed has a characteristically spade-shaped leaf with smooth edges and a defined point at the tip.
Photo of my evidence.
Japanese knotweed has a characteristically hollow stems with swollen reddish joints.
Photo of my evidence.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Fallopia japonica
Common name:
Japanese knotweed
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.675543 °
W -70.291580 °
Observation Site Information
A photo of our study site.
Upland - Forest
Trip Information
Baxter Woods
Trip date: 
Wed, 2017-07-26 19:07
Town or city: 
Portland, ME
Type of investigation: 
Species Survey


This does look like Japanese Knotweed to me! I have been pulling out the tiny Japanese Knotweed plants and they are similar to your photos. Good job with your Field Notes!