Despite its rather dull name, cow parsnip is a plant with an impressive presence. The giant toothed leaves (held up on stalks the width of celery) dwarf pretty much any other herbaceous perennial you'll find in our landscape. The giant white flat-topped inflorescence is icing on the cake. 
 
 
 
Cow parsnip prefers sunny to partly shaded areas with plenty of water. You'll find them along creeksides and in wet meadows, often with nettleleaf giant hyssop, large-leaf avens, thimbleberry, and lady and bracken ferns.