Marilyn they can be as tiny as 1/8" across a rosette or as large as 9" or larger across a rosette. Depending on the variety. But all make wonderful colonies.
Once you have a nice colony going, some in the colony will bloom while the others carry on.
The bloom stalks can be anywhere from 4" tall to over 1 foot tall, again depending on the variety of semp.
Maybe some of you here can show Marilyn some photos for examples of colonies?
Cruddy, I love them all.