Cut the bloom stalk off immediately, then remove plant from dirt, clean and dry it, then make a vertical division thru the rosette, dividing it into two equal parts. Dry again, then plant.
Include some stem and root on each part - that is important to allow it to regenerate the plant. One half may continue to insist on blooming, but the other half will likely not bloom. It will be set back and will likely develop offsets in a year or so. This is important - you will need to give the divisions extra attention to keep them alive and growing. I recommend potting them up and looking at them every day. Keep out of hot sun, mist the surface daily for a few weeks, but do not overdo it. The piece that decides to keep blooming may have additional surgery, if you think it is large enough.
Janice, I know you are an experienced semp grower, so this procedure should not be difficult for you. The key is to divide the plant and keep the pieces going. I've done this with larger rosettes and divided them in 4 or more pieces, but the larger the piece, the more likely it will survive.
I have been known to do vertical divisions of types that are really slow increasers. If you do it right, each time you divide a plant, you double the numbers - one becomes two, two become four, etc.
If you are new to semps or if you have not done vertical divisions before with them, then I recommend that you test this out on a variety that you have plenty of. Sharpen your skills (pun intended) so that you are ready when you need to use them to preserve a valued plant. This procedure is how I saved my S. Patrician. I had a larger, single rosette that decided to bloom. I divided it into 4 pieces, one of which insisted on blooming, but the other 3 survived.
