Hardy Perennial

I hope Agastache "Blue Fortune," is as hardy as the tag says it is. Last night i butchered the poor plant into 3 new plants and destroyed most of its root system. Plants make me do that to them. I see them and I can picture them growing into many more plants.
It was past 1 am and i kept walking past the plant while cleaning the house in preparations for the weekend. Expensive plants are supposed to be worth the money because they haven't been stressed and therefore will adapt better to the garden I remember reading in many gardening books. However I find that most plants (weather cheap or expensive) have been fed and exposed to light untill they are ready to bloom and then shipped to the stores for sale in small containers (veal comes to mind.)
Finally I stopped in front of the pot and took the plant out. It was 100 percent roots, so I took the hacksaw, (which happened to be near me) and a box cutter. First I cut in half, then i noticed one of the halves was still too crowed, so i made a third cut. The result was 3 new plants with flower buds and very small amount or roots.
Then I got stressed out because I only want what is best for the plants, but many times I wonder if I really know what is best.