There are three large (20') patches growing in the little forest across the street from my house. Two I can reach, one is down a slope and behind a safety fence...can't get at that one.

What herbicide sprays are effective? RoundUp appears to have had no effect at all.

I can grub out the accessible patches if I have to, but I need to find an effective spray to get at the one behind the fence.

Thanks!

Janet