Lygodium japonicum is what I'm guessing you mean by Japanese climbing fern. (Hai Jin Sha) ζ΅·ιζ²
There is one species of Lygodium that is
native to North America. L. palmatum is a temperate species recorded from Mississippi, Alabama, and Georgia northeast through New England. This could be a starting point. I've had very limited
experience with L. japonicum, but some friends have
land which have patches. From my understanding the plants like wet feet. Prefers a neutral to slightly acid soil, spread during wet seasons.
My first approach would be see if I could pull the moisture away from the area. I don't know the rules of your easement, but I might look into way of change the
water flow as it is currently. I would then try to ge t my hands on some L. palmatum. Plant it since it's a native and might complete. Another approach I might try to blackberries. I've personally seem blackberries out complete some pretty amazing plants. ( Like Multiflora
Rose) Another tactics I would try would be bunny tractors. Cut the plant down, and then let the bunnies dig and chew on the stems and
roots. Then move to the next stop since they are mobile it
should effect the easement.
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After some reading through some old science literature Rust (fungus) {Puccinia lygodii } has been know to restrict the growth. (Jones, 1987)
The value I've found.
The spores of this plant seem to have a good value in the natural medicine market.
And I also came across this idea. The extensive, fibrous
root system can be used as a growing medium for plants
Here is a start. Keep me updated I would like to know what you end up doing and what works and doesn't work.
Cheers
-Justyn