For insurance, I always put divisions of my favorite perennials in a number of different places in my garden. Then, if a plant dies out in one bed, the chances are good that it will survive in another location.
Since I have done this for some years now, I have a number of plants that, when in bloom, are repeated throughout the garden. This tends to unify the plantings in my garden and actually makes them look more coherent in design than I deserve them to be.
I noticed this particularly in the fall just past when the asters bloomed, and since some had also self-seeded, there were pink and purple flowers in many beds, pulling everything together in a colorful and satisfying way.
In mid-October when my pink Korean daisy mum ‘Sheffield' bloomed, it unified the beds too. Earlier in the summer, the unification role had been assumed by the blue/lavender catmint, which had self-seeded in many parts of my yard, and it required absolutely no assistance from me whatsoever.
All of the cranesbill geraniums are great unifiers, as well as doing a great job of stifling weeds in both sunny and shady areas.
Now, I'm on the prowl to find more of these types of perennials that have provided me with so much accidental unification. I love that they create an illusion that I am a gardener with an intentional design!