Soggy mulch would be horrible for roses. What about straw? Straw wouldn't mildew as much I think. That's one thing I never have a worry about is soggy mulch. Even with the floods we had last year where it destroyed towns up in the mountains (literally) did I have that much of a problem. Sure, my mulch was a soupy soggy nasty mess, but after about 2 weeks of drying winds it was like I hadn't gotten any rain at all.
