I tried growing broccoli for the first time this year, and I think I got it in too late. I live in zone 5B if it helps. As you can see from the picture, the plants are very big, but they've yet to produce any heads. I think two of the plants are in the process of bolting as they've sprouted long stalks in the middle that look like flowering buds. If they're "done," I'd like to take them out and try planting some other stuff.