Sorry, though for a split second my instinct was that cacti were monocots, of course they are not. They are actually Caryophyllales which is somewhat amusing if you think about it. (carnations with spines...you can see the vague semblance of floral form)

So there is no selective that will get rid of Charlie without also damaging or killing the cacti.

You are left either hand weeding the Glechoma...over and over and over, or trying some technique to create a physical barrier as you spray some amine-based selective or non-selective herbicide. (NOT ester selectives...the best for Charlie in a lawn is ester triclopyr, but the vapors from it could damage nearby plants if you're doing close-together spraying)

Standby for scaremongering posts about how using any herbicide will cause everyone in your family to get terminal cancer next week and end life as we know it on this planet in 3...2...1.

Hmm... I thought cacti were monocots too. Glad I asked before I did anything.

Please forgive my ignorance - I have never grown cacti; can they be dug up and moved? Or held somewhere while you dig up all the creeping charlie? I had to do that to get rid of one of those dreadful grasses that spread by underground runners, but it was just bulbs and peonies that I had to move. Again, I know nothing about growing cacti, so ignore if it is undoable.

Take a good look at the soil, and other growing conditions, where these are since they need pretty different conditions, although Creeping Charlie, " Glechoma hederacea" has adapted to a wide range of soil and growing conditions.

As a general rule "Glechoma hederacea" generally prefers soils that are compacted, moist, neutral or alkaline, while prickly pear likes a sandy, well draining, although alkaline, soil.

kimmq is kimmsr