The best time to plant full sun annual flowers is right after frost so they’ll be ready to pick or cut in the summer. Such certain flowers bloom very well under the sun. Another thing is that these plants are usually not too expensive unlike the perennials. Thus, annual flowering plants are a great start for newbies. The only downside is that the flowers of annual plants appear once in a year only or for some season and you have to replant again in order to get new blossoms.