100,000 Buckthorns to kill
I thought I would open this subject on my system for killing Buckthorn here in Mn. I have been working on my 3 acre plot for 5 years now trying to kill it all. There were about 50 large trees and many more small shrubs when I started. Cutting down the trees and shrubs opened up the canopy and subsequently, the plants suckered with 50 times more plants and the dormant seeds in the ground added thousandns more. So, my system now is to use strong doses of 2-4-d. I can get 65% 2-4-d at Fleet Farm for about $16/gal. Using a strength around 2%, I get the new growth in April and May before the native plants come up. This pretty well kills the new growth and most of the plant.
So, along with pulling by hand, digging with shovel, and dousing with 2-4-d, I estimate my total kill will be around 100,000 plants by the time I'm done(another 5 years, maybe).