Cosmos bloom late into fall when most annuals have faded, carrying burgundy flowers on tall, airy stems through October and beyond. They thrive in heat and poor soil—the worse your garden bed, the happier they are—and need almost no water or feeding once established.

Full sun, any soil, and they'll self-seed for next year if you let them. Deadhead to keep flowers coming, or leave the spent blooms standing for late-season texture.