I am a relatively new enemy of horsetail after moving to the Pacific NW. I have tried Roundup and Weed-b-gone and a couple of other things. The Weed-B-Gone lists horsetail and it does kill the above ground portion. But it does not appear to kill the mother plant underground. The underground system keeps putting up new surface plants.
I remove spore pods in the spring before they ripen (you have to check every day - they are incredibly rapid growing). I have been killing the surface plants whenever I find them for the last two years. The theory I am working on is to eventaully starve the mother plant to death. This is my second year of this approach and this years crop is way more than last year.
Anyone know of a way to eliminate these primative plants?