I've found that a moat filled with gently simmering hydrocloric acid (available from a swimming pool supply house) is an effective deterrent to creeping charlie...

seriously. that's something that you need a physical barrier both above and below the soil level to contain, and beating it back once a week during the growing season isn't too much- it may only take 5 minutes to hold that line, but it must be held.

I've never in my life seen pachys come down with a fungus...but I've taken out several roses and a grape rather than deal with the mildew and the black spot and the whatnot (in 5 years, I will plant RESISTANT strains in those spots. maybe)

but pulling out and disposing of any diseased plants and the mulch under them will be important, and a solution of baking soda and horticultural oil is said to make an effective antifungal.