My native flower are the windflowers. My "sister" flower are pansies. I have seen those two + hyacinths + tulips only in the beginning. I currently have the upgraded Nook's Cranny and I have seen the other flowers appear (roses, cosmos, mums, lillies). So, the other flowers WILL appear in the cabinet. However, I also time travel and from what I have been noticing, the native and sister flower remain, never changing. But the 3rd one DOES get changed out. It seems to be monthly, so for a month you might have all the roses available. Next month, lillies will replace roses etc. I will still keep track on this change but hopefully this helps! You are not locked to only certain flowers for the rest of your life.