In fact I can't think of any perennial that will change from pollination. The only ones that would are those that have seeds and the seeds, if pollinated from another plant, will give off a different color flower from the original. That is one reason ALL apples are grafted. The seeds from an apple will not give the same tree as the apple it is from. (that's what you get when you are a master gardener--all this junk stuck in your head)
Jodi