Control invasive weeds such as 'Wandering Willie' (Tradescantia Fluminensis) and 'Convolvulus' with herbicide. Spray only during warm, dry spells and be prepared to do follow-up sprays. Spray the whole plant, and then follow up with another spray two or three months later. You should also add a wetting agent or penetrant. It can take several months for herbicide to take full effect, and you may need to spray again to make sure it reached the roots. Small infestations of both these weeds can be dug out instead of spraying, but remove all pieces or they’ll re-sprout.