There are many flower seeds that can be planted in the summertime. Planting Calendula flower seeds will bring you flowers in September. They will readily re-seed and take a break from blooming during summer heat and then put on a show as temperatures fall in Autumn.
Although Calendulas don’t enjoy the extreme heat of summer, and do much better in the cool temperatures of spring and fall, they will continue to display their blossoms through fall and encourage new growth if regularly deadheaded.
Calendulas are not true marigolds but are sometimes called pot marigolds. They are perennials in Zones 9 to 11 and annuals in Zones 2 to 11.