Why aren't my lupins flowering?

Sounds like your soil may be high in nitrogen. Apply a high potash liquid feed and this should start to help them.

Yes, they are perennial though the root stock generally starts to get quite woody after a couple of seasons with the plants losing some of their vigour so either new plants or cuttings can be used to replace the original plants.

they are short lived perennials 3-6yrs typically and if they were grown from seed this year then they may not flower this year. but they will next year. some of mine did in their first year but most of them didnt until this year.

Forgot they can be grown from seed too Lol

all mine are as i begrudge paying silly prices for them.

I bought mine as small plants from a garden centyre this year, and they are large and flowering, some are just opening, some are still green buds, and others are in full flower.

I waited months, watching the leaves grow huge, and the flowers are well worth the wait.

Thanks folks. That's all really helpful.