Invasive SpeciesJapanese barberry

Berberis thunbergii
FOUND by Fungus
Portland, ME
ID Confirmed
Quality checked by Fungus
Peer reviewed by
Field Notes
Somewhere in the middle of Baxter woods lies a clearing, occasionally mowed and used for various functions. On this overcast, slightly rainy day, I can hear the insects and birds alive around me. Far away, I can faintly make out the hum of cars zipping along Forest Avenue. The rain we had earlier this morning threatens to continue, while the sun currently works to fight its way out from behind clouds. Baxter Woods is notably cooler than the surrounding neighborhood. During my Field Study, I have seen several people who decided to take advantage of the temperature, and the break in the rain, to briskly walk their dogs along the trails.
Supporting Evidence
Photo of my evidence.
The stems of my plant grow in a zig-zag pattern with one thorn at each joint.
Photo of my evidence.
The leaves of my plant are simple, oval, and smooth. (Therefore I can rule out European and American Bayberry which have toothed edges on their leaves)
Photo of my evidence.
My plant has green berries on it. Japanese Barberry has small white flowers in April and red berries after September, so the timing seems correct for me to find the developing green fruit.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Berberis thunbergii
Common name:
Japanese barberry
Count of individuals: 
Between 1/2 and 3/4
Fruit (plants)
Sampling method: 
Quadrat (user-placement)
Photo of our sampling method.
Place Studied
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Map this species
N 43.677620 °
W -70.292120 °
Observation Site Information
A photo of our study site.
Upland - Forest
Trip Information
Baxter Woods
Trip date: 
Sun, 2010-07-11 11:00
Town or city: 
Portland, ME
Type of investigation: 
Species and Habitat Survey
Habitat Observations
Species diversity: 
8 different species
Evidence of vectors: 
Dirt road
Walking trail
Recent disturbance
Tree canopy cover: 
Open to 1/4 covered
Soil moisture: 


Without a doubt, you've found Berberis thunbergii. I'm interested to know how widespread it is in Baxter Woods. Did you notice it on your trek in or out? Is it mostly along the trails and at the edge of clearings, or have you seen it under the forest canopy as well?

Thanks for looking, finding, and reporting in such fine fashion. Your observation is thoughtful, complete, and very nice on the ole eyes!