P Williamson wrote:
My horsetail experience
Years 1-3 dug every piece of top and root of horsetail out of plot - almust
sieved the soil. Pulled up every piece that showed up every week.
Years 4-9 hitting it hard every year. Experience of covering with
carpet/plastic seems to encourage it too spread and anyway after covers
removed if seems even more vigouous

Your story is my story indeed!

Mel, divide your plot and start at the beginning working bit by bit
removing the weeds as you need the ground. Year 3 and I don't find it
so much anymore. It does, like P said, seem more vigorous if I cover
some areas - it seeks the light from miles away it seems. According to
your lotty pictures you have a good size plot with plots arround being
used. I wouldn't, and never has, used weed killers. Stay on top of your
weeds, dead heads them/dig them out as you cultivate your plot,
eventually they'll diminish in quantity. Don't get a headache with your
weeds, rather enjoy the pretty ones and just dig dip for the ones in
the way )