they're not perennials, cole crops are biennials (except for mustards and radishes). If you let this thing grow, it will try to flower this year.

Though from my understanding if you cut off the flower stalks before they flower a cole crop can be persuaded into staying alive/being perennial, there is a "perennial kale" you can do this with. You also have to consider if you pulled off the growing tip/cabbage thing last year - it will have trouble growing more if you performed that practice (that is cutting the cabbage-shaped top of the brussels sprout plant which is actually where it grows taller and taller from)

I would just re-plant a new brussels sprout as part of my crop rotation, and try to successfully get some decent sized sprouts.

Also remember that brussels sprouts don't like hot weather - so you would have tro deal with that if you did manage to grow it as perennial

Yeah, it is just going to seed. No sprouts in the second year. Depending on the variety you can save the seeds if you want to let it get that far but most likely it is a hybrid so won't breed true.

Dave

Thanks for the info. The Brussels sprout has gone to the great garden patch in the sky, otherwise known as the compost bin. Tomorrow I shall ready the bed for potatoes.