A few days ago I noticed about a one-foot wide band of dog fennel (Eupatorium capillifolium)on the dam at about one foot above the current water level. It is actually about a foot lower than the full pool level; the pond never reached full pool last year, because I was irrigating the new grass from the pond.

I'm debating whether to try to kill it, and if so, what to use that would be safe that close to the water. Or would it drown on its own once the pond fills and covers it with a foot or so of water?

And does dog fennel have any redeeming qualities that I should consider? I have heard that some butterflies like it.