Today I pulled a half dozen first year Broom plants located in our ‘100 acre Wood’ named for the reference to Christopher Robin rather than its actual extent.
This forest appears to be about 40 years old and is separated from the former meadow pasture by an old cedar snake fence. It also has remnant cedar stumps. The understory is mixed with lots of Trailing Blackberry and slowly establishing Oregon Grape, Salal and Sword Fern.
Broom is thought to not be a problem once the forest grows up. However these seedlings keep appearing though there has been no seed source here for 10 years.