Posted: 16/05/2016 at 19:41
I have used nematodes for ants in lawns successfully. No reason why they shouldn't work in a border.
check for aphids though on your rose bush....ants are prob "farming" them.
Spraying with water may help....is it dry there?
You could excavate around the roots and see if there is a nest there. Trickle a hose there and I find this effective.
I don't think ants are "eating" your buds though mjd2000