I think it might have been Daniel that posted once, that it was best not to mulch most plants with parts of themselves. I had never thought of that, but once I read it, it seemed to make good sense. The logic behind it being that for example daylilies:
The dead leaves and scapes might contain diseases and pests that would harm daylilies. I don't know of any scientific studies done on that but I now remove all dead leaves and scapes from the garden. I would love more feed back on the subject. Maybe people have mulched with the dead leaves and scapes and had no problems?