I'm curious how many years peonies, phlox, and lupines last if you just leave them in one spot and don't touch them? Do you need to refresh them somehow or do they maintain themselves?
Peonies can grow in one spot for decades with almost no intervention, but phlox and lupines start to degrade and get smaller after about 4-5 years without division - they need to be periodically rejuvenated by digging up and splitting the clump. Peonies are the easiest: they're real long-lifers and can easily live in a garden for half a century if you leave them alone; phlox and lupines use up the soil more actively and get dense in the center, so it's worth dividing them every few years so they don't lose their ornamental appeal.
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