I think the first flowers I ever planted as a kid were marigolds, and they have always been among the elements of any flower garden I have planted. I like the fact that marigolds provide many months of color for a relatively small investment, and of course these are hardy plants that need little maintenance beyond an occasional watering. In fact, marigolds tend to thrive just on the edge of dry soil, as this forces the plants to root deeper.
Some horticulturalists despise marigolds, citing reasons such as their prolific spreading, their strong aroma, or the ease with which any schlep can grow these flowers. Yet I like to use them as border plants and to fill in areas that need some future work but which I do not have the time to invest. For example, one of our weigela bushes died last year, so I simply tossed some giant marigold seeds in the space and voila! Instant color.
I typically grow marigolds from seed, getting the seeds in the soil as early as possible. In my front yard the flowers began to appear about the 20th of May this year, and I will continue to have color from the marigolds until at least mid-October. That means about five months of color for perhaps three dollars worth of seed, and if I remember to harvest the seeds this year, these flowers will pay dividends for years to come.