I have bronze fennel in the garden just for the insects. I've had the same stand of plants for the better part of a decade now. Their lifespan is a few years, but once a root cluster gets established it will keep reseeding and coming back. I consider it one of my best companion plants out in that part of the garden. It's also pretty :) Every once in a while I harvest some seed for pickling with. Otherwise I don't eat it, it's not my speed. It does self seed quite easily so I pull up little seedlings every year as part of the regular weeding. During the summer I might cut back a couple stalks if they get too rambunctious over the other plants, but I mostly just let it do it's thing. Otherwise I don't cut the dead last years growth down till Spring clean up after the insects have woken up.
We do like bulb fennel. I tried growing it from seed last year. Not a great job, I'll do better this year.
Q