How long from offset to blooming size?

So I've saved a couple of the biggest offsets from my Apple Blossom. They're a little over an inch in diameter, and growing fairly happily (I think) in a small clay pot, together. But not *too* crowded. How long will it take to grow them to blooming size, given that they live in Minnesota and can't get months and months of lots of heat? Though I can supply pretty nice conditions from May to September, of course. This is more a case of horticultural curiosity and personal challenge, than of saving money on buying bulbs.

Oh, and PS re offsets - other plants are developing a few here and there too. Should I remove those, as a general rule, when re-potting?

I'd give them at least 3 years, maybe more. If you are trying to encourage the bulb to bloom next winter, you probably would want to remove the offsets.

Thanks!