Peonies are susceptible to several diseases including botrytis, which can cause large dark blotches. At this time of year it is safe to cut them back for the winter. If it is botrytis, this is an imporant control because the disease overwinters on the foliage and infects the flower buds next year. Not sure what is going on with the elephant ear. If only a few, cut the affected leaves off. The black leaves could be a symptom of many things. Without more info it's too difficult to diagnose.
