I have a strip of dwarf mondo grass down the middle of my driveway. Pennywort has started to grow in amongst it, and is gradually spreading and taking over.
I have tried manually weeding it out (was spending 10 or 15 minutes each day), however it's coming back as fast as I can remove it. Because of the mondo grass roots, it's very difficult to get all the pennywort roots out.
The mondo grass is growing quite well in areas the pennywort hasn't reached yet.
Is there anything I can do? Can I change the conditions to suit the mondo grass more than the pennywort and give it a better chance?
I don't mind using a herbicide if required. I'm not much of a gardener so any help is appreciated.