I've come a bit late to this, but here goes.....My crowns have been going for 35 years. I never water them, they are next to my JA's with no problems, and they only get mulched if I have compost to spare. My biggest problem is asparagus beetle,but not every year, this year I only caught a few right at the beginning (late march for me). So my conclusion is that once they get established nothing will stop them.