Q&A: Killing Dollar Weed
Q: What would kill (forever, if possible) dollar weed that's growing with my pachysandra? It's almost impossible to pull up before you pop it off. Can I apply an herbicide without hurting the pachysandra? I also have an overabundance of oxalis that I would love to permanently destroy. Any suggestions?
A: Unfortunately, there's no post-emergent herbicide that will target your weeds without risking your plants. You might try a pre-emergent herbicide to prevent the oxalis from reseeding. The best approach would be to mulch well after you hand-pull the weeds and then make sure that any new oxalis and dollar weed face stiff competition. Apply a foliar fertilizer to the pachysandra, and if there are any "dead" spaces in your bed, put in more pachysandra (or other desired plants).