Beginner Gardening: Why didn't this annual (from last year) die? , 1 by gsbird

gsbird wrote:
I am growing bidens pilosa and I think it is supposed to be an annual. Last spring I sowed the seeds (bought online) and it grew well, flowering, attracting bee(s), and setting seeds which I collected. In the winter it withered away, I trimmed it but I didn't toss it. This spring, leaves came back and flowers too, but so far no bees came, and the plant does not grow tall.
What is going on? I am in the San Francisco bay area. I would like to know if I should toss this plant, or re-pot/fertilize if there's still hope for another season. I am growing it for the seeds.
Thanks in advance for any advice!