One day a wife picked a rose from a magical bush. Little did she know the rose bushed was cursed by a witch and who ever picks a rose from her bush gets turned into a rose and put on the bush. The only way she can get turned back is if her husband picks her as a rose, if he picks the wrong one though he gets turned into a rose also. But here is the thing, the wife has 3 kids and convinced the witch to let her be turned back into a human for the night to see her kids. The next morning he went to the Witch's rose bush and saw 20 roses. After looking at every rose he picks a rose and his wife appears in front of him.
How did he know which rose to pick?