How many crowns?

Hi all...just coming into my third season on plot 4a , and have still not got to grips with the Rhubarb.Basically to cut the saga short, the crown was a division given to me by my neighbour, which was duly planted...then got moved...and then again to is final(!) resting place, miracles were performed and it sprouted about a month ago, first one, two, then three stems............then Mrs Urbanite in her size 4 duck boots decides to jump up and down on the crown(it seemed that way at the time...words were exchanged).Anyway this wasn`t supposed to turn into a saga, so i`m gonna buy new,I have a 4`x4` raised bed that I was gonna use for salads, but have decided the Rhubarb could do with the extra fortification a raised bed offers...so how many crowns..1,2,3 or 4
TTFN Urbz.