Unfortunately I have found no easy way to eradicate the vinca (Vinca major or minor) or English ivy (Hedera helix) other than grubbing them out. This is not really a major job with the English ivy, but with the vinca you must get the rhizomes. Oxalis, if in an area where the killing of other vegetation such as turf grass is a concern, may be killed using a herbicide such as Atrazine, Triclopyr or 2,4-D. If it is where you can spray it without worrying about other plants, then one of the glyphosate herbicides would be my choice.