What is plant fertilizer is better miracle gro or vigaro?

The fertilizers you mention are artificial "junk food" for plants - fine for showy annuals which are expected to die at season's end, but not at all the thing for healthy perennials. To feed your plants, you must feed your soil, that is, the microbes that convert nutrients into a form that the plants can ingest. A delicious compost diet, supplemented with worm castings and lots of organic matter (all made at home, practically free) will establish a healthy balance in your soil, and maintain strong, sturdy plants. Some plants, however, bloom more profusely in depleted soil (putting forth flowers, and therefore seeds, is a biological survival response to poor conditions). For the most part, organic compost is the way to go.