This is horsetail. We have a lot of it here at Mucky Boots, in all the damp areas around the pond and the aquifer at the back of the property. It's a prehistoric, primitive plant, and there's a reason it has survived so well: it's indestructible. It is impossible to get rid of horsetail - it even grows through cement.
But we have a secret weapon: our chickens. They have decided that the tender horsetail fronds are a delicacy, and have been decimating the horsetail forest around the pond like there's no tomorrow.
We think the chickens started hanging out in the horsetail forest as a way of sheltering from the heat and the eagles overhead, but in no time the forest began to look like this.
I'm sure this will just put a momentary dent in the forest, and the horsetail will regrow quickly. But in the meantime the chickens are happy!