It was growing well, as can be seen on the picture: (March 10th) After a month, it was clear there were not only flowers growing! (April 4th) Another month later (May 18th): And from another angle; you can clearly see the new leaves try to form their own rhizome Final result: (June 9th) In the end, I was able to snap off the new leaves after the flowers were dried out and the stem started to die off. I kept them alive for a while until they died from dehydration (....oops)
From the dried out flowers I harvested quite a lot of seeds. I have yet to sow them and see if they are any good!