Ducks and trees in Southland

Hi all. My wife and I have moved onto 7 acres in Invercargill. It is divided into duck ponds, lawns, and trees. Loving it. Lots of work though! Anyone have suggestions for controlling willow herb? It's everywhere under trees and in the driveway. Glyphosate doesn't work

Chris

Glyphsosate and some penetrant (dishwashing liquid )

Glyphosate, even with a penetrant, will kill the grass in preference to the "flat" weeds. By using this you will end up with a dead patch that the weeds will rapidly regrow in. I use MCPA as my preferred flat weed killer but it is hazardous to some garden plants if they get a smell of it. Grazon or one of the Tordons are safer and kill more.