Due to our ignorance, the first appearance of garlic mustard (Alliaria petiolata) in our yard was met with enthusiasm.  The first year plants have cute heart-shaped green leaves and we were pleased to see something sprout. In a short time a fairly large area was covered in a fluffy green carpet. Soon after we identified them as aggressive non-natives and removed them from our yard. You will have to look elsewhere for pictures of the mature second season plants which have an upright growth habit.