Beginning Garden Primer: Elements for First Garden Success → A Successful Garden Plot →Fast Growing Annuals
Annuals are programmed to flower, set seed pods and mature seed in short order.
Flowering Annuals are a perfect landscaping tool as well. When you need
some quick fillers use them abundantly while you prepare a
new garden design.
The planting time for annuals varies according to climate and plant. Cool-season
annuals like Sweat Pea and Floss Flower (Ageratum) grow best when both weather
and soil are cool.
It depends on your hardiness zone but in my experience Floss flower can bloom
from early spring until autumn.
The Marigold and
Sunflower
are typical late bloomers. The Sunflower tells the story of the
oncoming change of season with so much style and dignity that a slight onset of
nostalgia autumn can bring about will vanish to thin air.
Snapdragons and Pansies

If you want to make the most of them you must – deadhead them, snap off faded
blossoms before the plant can make seed.
That way new blossom will replace the old ones. In fact you have made the
plant believe it hasn’t finished yet.
I
f you prune faded foliage as well, you can even have them bloom with more
exuberance.