Invasive SpeciesGiant knotweed

Fallopia sachalinensis
FOUND by 18ka
ID Confirmed
Quality checked by Ms H
Peer reviewed by VA
Field Notes
For our marine study, we used a transect zone collection method there were 8 groups each with 5-6 students. The day we went out it was cooler and windy in the morning but got progressively warmer as the day continued. My group had an area that was mostly covered with seaweed and algae such as knotted wrack, and spiral wrack, this caused the area to be very slippery and also allowed for many places crabs could use to hide. Also in our marine area were many big sloped rocks with overhangs above the ground with walls of knotted wrack covering openings. We found 10 crabs which were all European green crabs and of the male gender, the biggest one of the bunch was 7cm wide and the smallest was around 2cm wide. Other species found in our area were Common periwinkles (15 upper intertidal, 14 lower), Rough periwinkles (12 upper intertidal, 10 lower), and one Smooth periwinkle found in the upper intertidal zone. When we went on the path around the island we saw many different invasive species taking over multiple different areas such as Giant knotweed, Japanese barberry, Asian bittersweet, Glossy buckthorn, and Morrow’s honeysuckle. All of these plants were taking up quite a bit of space but the ones taking up the most room in the area were the Giant knotweed, taking up an area of about 52 meters by 10 meters, and Asian bittersweet, it was wrapped around and taking over many trees, and shrubs all along the path and even more so away from the path in plants around small fields. All in all this place needs lots of work and lots of time but it may be able to recover if people to help are found quickly and is the work done is efficient, if not this island may be too far gone to save.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
Leaves are bigger than Japanese Knotweed and are heart-shaped, Japanese knotweed leaves are not. The leaves are also an alternating pattern and have raised veins.
Photo of my evidence.
The branches have swollen joints and go in a zig-zag pattern (also has a hollow stem)
Photo of my evidence.
Clusters of white flowers that are smaller in length than the leaves themselves.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Fallopia sachalinensis
Common name:
Giant knotweed
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.690314 °
W -70.226834 °
Observation Site Information
A photo of our study site.
Coastal - Beach or dune
Trip Information
Mackworth Marine Transect Investigation
Trip date: 
Tue, 2018-10-09 07:36
Town or city: 
Type of investigation: 
Species Survey
Time of low tide: 
Wed, 2018-10-03 10:15


Good job. Is the shape of the leaves the only difference between giant knotweed and just knotweed?