The broccoli has been prolific in the amount of stalks it produced, but unfortunately the taste has been mediocre at best. Also, the timing required to harvest the stalks is incredibly precise; a day early and it is too "green" tasting and a day late means the florets bloom. I'm calling this little experiment complete and have let the plant go to seed.
Since I've stopped cutting the stalks, new florets have not grown very much. Most of the plant's energy seems to have become focused on putting out flowers. You can see what it looks like now in this photo taken this morning.
Broccoli is a member of the same family as cabbage. There is an apartment around the corner from me that has ornamental cabbages growing in the lobby. You can see the similarity between the flowers of the broccoli above and the cabbage below.
I'll bring the broccoli indoors soon and put some seed-catching paper around it to prepare for next year. I think I need better soil and probably better weather than we've had this year. This winter has been holding on too long.