Most herbaceous flowering plants, especially annuals, grow best in a flowerbed, with soil that is regularly dug over and supplemented with organic matter and fertilizer.
Because flowers bloom at varying times of the year, and some plants are annuals, dying each winter, the design of flower gardens usually needs to take into consideration maintaining a sequence of bloom and consistent color combinations through varying seasons.
Many, if not most, plants considered decorative flowers originated as weeds, which if attractive enough would sometimes be tolerated by farmers because of their appeal.
Sunflower Once domesticated, though, most flowers were grown either separately or as part of gardens having some other primary function.
The best mixtures even include combinations of perennial and biennials, which may not bloom until the following year, and also annuals that are "self-seeding", so they will return, creating a permanent flowerbed.