Same here, Imperial Star. Although I grew some back in the late '80s that was when my soil wasn't up to snuff (fairly fresh-cleared land). I had beautiful plants but no buds. Have no idea which variety those were back then either.
Last year (or year before) I got Imperial Star (Johnny's Seeds) and had excellent results! It can take quite a while for some of the seeds to declare but I got quite a few to germ by soaking them a day or so. I start them in row flats then, like moms2goldens did, move them up to 4" pots. It's cool enough here during the nights in Feb/March/April to get the required vernalization time in .
I harvested some buds first year, fairly small but tasty! They should be perennial here but I found out the deer like them more than anything else in the garden. Hopefully I'll raise my fence height this year before it's too late, or keep them covered in row cover if needed.
Imperial Star artichoke seedlings (before true leaves)
Imperial Star artichoke seedlings moved to 4" pots:
Small Imperial Star artichoke bud
I'll have to see if I have better pics of the whole plant and put them in the database.
Shoe