5. Coneflowers
There are several genera of flowers referred to as coneflowers, but the two most common are Rudbeckia and Echinacea. Many will likely recognize Echinacea was the beautiful purple coneflower that is often used in cold-fighting herbal remedies come winter.
Coneflowers, in general, are drought hardy flowers that can withstand a great deal of heat and sun. They are easy to gather seeds from, making them an ideal seed-starting project for the cold winter months. A specific example on this list are the Black Eyed Susans.