Erinus alpinus is best scattered where you want it, on a patio, gravel, between paving stones. I have never found it easy in pots but if you have plenty of seed it is great for making a lovely show at this time of year on areas which might be difficult to establish full size plants. I gave a friend a bag of seed and she put it on a table, the wind blew it off and the seed scattered about her terrace, what a great show she had the next year.
Susan