It is a stretch to make empirical statements about other environments but, in the middle of the country where I am, I found peonies like to be dug and divided every 5 or 6 years. They seem to thrive when moved to new soil. I suspect it is from their consumption of the micro nutrients in the soil which fertilizer just cannot replace. Here in farm country, crops are rotated from corn to wheat to beans and repeated. Helps to reduce diseases also,
