I tried growing Echinacea in my patio area and they seemed to take off quite
nicely, but knowing nothing about them, I left them alone to do their own
thing.

I read somewhere about deadheading them, but didn't do that as I am not
familiar with the practice.

So right now I have the plants in my little plot, looking perfectly dead and
wondering if they will come back in the spring or did my ignorance turn what
should have been a perennial into an annual? How do echinaceas seed and
grow - by the flowers, like marigolds, or some other mechanism?