Creeping Woodsorrel (Oxalis Corniculata) What does it look like?: Short, typically no taller than 4 inches.  It is a spreading perennial with 3 hairy heart-shaped leaves of reddish-purple and yellow flowers with 5 petals. What causes it?: It often comes home with you in plant nursery containers–it loves warm, moist environments, but is incredibly adaptable.  It spreads through its