Take for example, garden phlox. I have a pure white form of Phlox paniculata, 'David', that is extremely healthy and vigorous here in Kansas and I have divided it several times in my garden. My fondness for this plant may have a little to do with the fact that I have an adult son named David, but it also has to do with the fact that this is a very low-maintenance plant for me, needing little more than a haircut each spring. It is just starting to bloom this year and while I have several pure white clumps blooming on the south side of the house, the north side plant just recently began to bloom as pictured at the right. The early blooms are magenta, although the remaining 3/4ths of the plant looks like it will bloom the normal white form, albeit a week or so from now.
I don't know about you, my fellow gardener, but I much prefer the all-white form pictured at the left, and therefore the "bad" 'David' is going to get ripped out at the roots. I don't know if this was a mutation of a portion of my plant or simply some wild reseeding going on adjacent to the original plant, but the magenta parts have to go. And soon. Sorry, God, but my view of the Garden of Eden includes the philosophy that white is "good" and magenta is "evil."