Pollen tubes grow through the stigmas and styles of female organs, eventually penetrating the ovary where the sperm is released to fertilize the eggs. This is a sex act and may involve birds and bees. By the time the fruit is formed, it is too late for birth control. Possible mechanisms involve use of offspring, growing into new areas. Note that pollination and fruit dispersal or seed dispersal are very very different.
Perennial plants live for many years.
Usually this means that they have many chances to reproduce. Each reproduction event is a chance to move. Howe and Westley chapter uses numbers in the hundreds of thousands or millions of seeds a year. Producing seeds or babies or eggs does not guarantee their survival, however, and the hazards of moving at this time in a life cycle are so great that the vast majority of the offspring don' t survive. There is a trade off, though.